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Hard coatings for decorative applications
Surface and Coatings Technology, 36 (1988) 829 - 836
829
HARD COATINGS FOR DECORATIVE APPLICATIONS* H. RANDHAWA Vac-Tec Systems, Inc., 6101 Lookout Road, Boulder, CO 80301 (U.S.A.) (Received April 11, 1988)
Summary Reactively deposited films of TiN and ZrN are of great interest as decorative coatings and in architectural glass applications. Traditional methods of film deposition have posed problems related to available deposition rates, film quality and color control. The cathodic arc plasma deposition process offers an alternative to deposit such films with good uniformity, film quality and color control. This paper deals with hard coatings for decorative applications deposited using the cathodic arc process. The films of TiN, ZrN, HfN, TiA1N and TiZrN are characterized in terms of structure and morphology, colorimetric and optical reflectance, hardness, wear resistance and corrosion resistance. It is demonstrated that by adjusting process conditions, doping with carbon and/or alloying with other elements it is possible to adjust coating colors over a wide range and to simulate closely a range of gold colors. The cathodic arc therefore provides a significant alternative to existing techniques for a wide range of decorative applications. 1. Introduction The group IVb nitrides with their gold-like colors have generated a great deal of interest [1 5] as economical, hard, scratch-resistant decorative coatings. With the recent developments in plasma enhanced physical vapor deposition processes, hard films of negligible self roughness have been made [6, 7] at temperatures as low as 300 °Con substrates such as stainless steel. Earlier studies [1, 3] on the color of TiN films deposited by ion plating or sputtering indicated that the films varied with the deposition conditions, method of preparation, etc. A very careful control of deposition parameters, such as deposition rate, nitrogen partial pressure, substrate temperature, etc., was needed to ensure reproducibility of color and consistency. The cathodic arc plasma deposition process was considered to be unsuitable [8] for decorative applications until recently, owing to the presence of macroparticles in the film. The latest developments [4, 8] involving the -
*paper presented at the 15th International Conference on Metallurgical Coatings, San Diego, CA, U.S.A., April 11 - 15, 1988. 0257-8972/88/$3.50
© Elsevier Sequoia/Printed in The Netherlands
830
elimination of macroparticles in the cathodic arc process have provided a significant alternative to existing techniques for a wide range of decorative applications. The cathodic arc process also offers a great deal of flexibility; e.g. the control of deposition parameters is less stringent than in magnetron sputtering or ion plating (the magnetron sputtering and ion plating processes require control of the partial pressure of the reactive gas as compared with control of the total pressure in the chamber in the cathodic arc process) and the deposition temperature can be adjusted and controlled over a much wider range thus enabling substrates such as zinc castings, brass and even plastics to be coated. 2. Experimental details The films investigated in this study were prepared on ASTM 304 lapped stainless steel samples (size, 1 in X 2 in) using an ATC 400 production-type cathodic arc plasma system. The system is described in detail elsewhere [4]. A substrate to source distance of 10 in was used. A reactive gas of nitrogen in the case of nitrides and acetylene in the case of carbides was used. The incorporation of carbon in the nitride films was achieved by using a mixture of nitrogen and acetylene gas. The film composition was varied by varying the gas flow rates of the reactive gases at a constant metal evaporation rate and constant substrate temperature of 300 °C.Typical deposition rates were 0.3 j.tmmTorr. min1. The total pressure in the system was varied in the range 2 -10 The films were analyzed for microhardness using a Knoop microhardness tester at a load of 20 gf. The compositions of the films were studied using scanning Auger microprobe analysis (SAM) and electron spectroscopy for chemical analysis (ESCA). The color coordinates L*, a* and b* were measured using a Hunter Labscan II with a d/8 geometry and D65 illumination. The heat treatment applied here was based on earlier observations [9] that an expanded and distorted crystal lattice contracts towards the equilibrium value during annealing at elevated temperatures of up to 500 °Cin air. Above this temperature, TiN and ZrN films were found to discolor due to oxidation. The effect of aging on color was studied by storing the samples in air at room temperature for a period of 6 months. The effect of corrosion on color was studied by exposing the coated samples to fuming HNO 3 for 72 h and salt spray for 72 h at room temperature. This simulates the exposure to human skin for several years. 3. Results and discussion 3.1. Deposition process
The deposition of the films was carried out using a cathodic arc plasma deposition process. The process is described in detail elsewhere [10]. Con-
831
(b)
(a)
Fig. 1. Scanning electron micrographs of TiN films obtained by (a) a conventional arc process and (b) a modified cathodic arc process.
ventional vacuum arc processes [11, 121 suffer from the presence of droplets in the deposited films and are thus considered to be unsuitable for decorative applications. In this study, a modified cathodic arc process was used where the droplets are eliminated in the coating. Figure 1 shows a scanning electron micrograph of TiN films obtained using a conventional vacuum arc process and the present modified process. It can be seen that the droplets are eliminated in the TiN film produced using the modified process. This modified arc process is described in detail in a separate publication [4]. 3.2. Color: as-deposited films
The color was measured with a Hunter Labscan II using D65 illumination and d/8 geometry. The data for TiN and ZrN are shown in Table 1 in the as-deposited condition. It was found that in both TiN and ZrN the a* TABLE 1 Color coordinates of various as-deposited hard films Sample
Composition
L*
a~’
1 2
TiN TiC
77-80
3 4
0~N095 TiC010N0~ TiC0
76 - 79 71-75 66 - 69
5.5 - 8 8.5-11 ii - 16
30 - 33 23-28 21 - 22
5 6 7
ZrN ZrC010N0~ ZrC015N085
86-89 81 - 84 79-81
—3-—i —i -—0.4 0-3
23-25 26 - 29 17-19
8 9
Gold,i0karat Gold, 24 karat (pure)
81-86 88 - 91
—1.6-i —37 - 1
19-30 27 - 34
2-5
b* 33-37
832
(redness) and b* (yellowness) parameters varied with the nitrogen level. Simlar results were anticipated for TiN films by earlier workers [2, 3]. TiN films obtained using the ion plating process possess a color that is greener than the standard color of yellow gold. In contrast, sputtered films are slightly brownish in appearance giving more redness in the film. This has been attributed to the columnar microstructure and to the slightly overnitrided films typically obtained from sputtering. It was found in this study that the color of TiN deposited by the cathodic arc process was closer to yellow gold. This is illustrated in Table 2. Furthermore, it was found that with the nitrogen pressure in the range 5 10 mTorr the color of the TiN films was fairly consistent in terms of L*, a* and b* values, thus giving a wider range of operating pressures and enhanced reproducibility. It was also found that the substrate temperature above 250 °Chad no noticeable effect on the color. Similar studies carried out using magnetron sputtering show a variation in the color of the film due to a variation in substrate temperature [15]. -
TABLE 2 Comparison of color coordinates of TiN films obtained by various deposition processes Process
L*
Composition
Sputtering Ion plating
75 74
-
77 80
3- 8 0.5 - 10
25 20
-
35 30
15 TiN TiN~
Cathodic arc
77
-
80
2-5
33
-
37
TiN
05
By introducing carbon into the TiN and ZrN films it was found that the color could be altered significantly. The introduction of carbon was achieved by using acetylene gas in the mixture. Table 1 lists the relative L*, a* and be values with increasing concentrations of carbon in the films. As is clear from the values listed in Table 1, a pronounced shift towards the red results from the incorporation of increasing amounts of carbon in the films. Thus carbon contents can be adjusted to match desirable gold colors. On alloying titanium with suitable elements, such as zirconium and aluminum, it was observed that the a* and b* values of the corresponding nitrides could be suitably matched to standard 10K gold or 24K gold colors. These results have been reported previously [7].
The color of the nitrides and their metallic luster are due to electron transitions in the energy band. It is these electrons which, on relaxation, emit yellow gold light and their number is a measure of brightness. The introduction of carbon into TiN or ZrN films reduces the number of energy states to which electrons can be excited, and thus the brightness is lowered with increasing contents of carbon as shown in Table 2. Similar results have
been reported previously in the case of oxygen incorporation [1]. The effects on the color of the group IVb nitrides have been described previously in terms of a simple qualitative ionic model.
833
3.3. Microhardness The microhardness measurements were carried out on various nitrides and carbonitrides using a Knoop indentor and a load of 20 gf. A film thickness of 3 pm was used. Results of these measurements are shown in Table 3. As is clear from this table all the films have microhardnesses in the range 2400 3450 kgf m2, and thus are quite hard. The films were also found to be very wear resistant compared with gold films. In a typical wear study involving tumbling the coated parts in an abrasive medium of metal filings, gold film with a thickness of approximately 1 pm was worn in less than 10 s whereas for most of these hard coatings several hours were required for comparable wear. -
TABLE 3 Color and microhardness of films Composition
Color
Hardness (kgf m2) (15 gf)
TiN ZrN HfN TiC~Ni_~(x 0.05 -50) ZrC~Ni_~ (x = 0.05 - 20) Ti~Ali_~N(x = 0.1 -70) Ti~Zri_~N(x = 20 -80)
Golden yellow Golden green Yellow—green Reddish gold—brown Golden Golden, brown—black Golden
2400 3200 2750 2450-2900 3250 - 3450 2400 -2900 2400 -3250
3.4. Aging and annealing effects Mononitrides of titanium, zirconium and hafnium were found to age significantly in terms of color. These films tend to darken with time. Figure 2 shows the effect of aging on the color coordinates for TiN, ZrN, carbonitrides and TiZrN over a period of 6 months. It is interesting to note that most of the aging occurs in the first several days and then it tends to slow down. The results on the carbonitride films and the films of alloy nitrides are included. From these results it can be seen that carbonitrides and alloy nitride films hardly age at all compared with minor nitrides. Perry [9], using a simple ionic model, attributed the aging effects in TiN and H!N films deposited by ion plating to lattice contraction to equilibrium values. However, there are also other surface-induced effects, such as surface film oxidation due to exposure to air, that are only surface related and not a bulk phenomenon. Further studies to understand this behavior are currently underway. The effect of annealing was investigated by heat treating the films at temperatures of 100, 200, 300, 400 and 500 °Cfor a fixed period of 1 h in air. The color coordinates were monitored before and after annealing. The results are shown in Fig. 3. There are no significant effects on color in the various films up to 300 °C. However, the color coordinates of TiN film
834 5
—
4
-$j
-
T~N I
I
I
~
~
40 30
ZrC •
1~N005
a
A_
A
0
I
2 TIME MonthsI
5
6
Ti0~Zr0 N 1
x
s ~
x
n
i.
~
x ZrN
-2
-3
Fig. 2. Color coordinates of various hard films.
annealed at 400 °Cfor 1 h and ZrN film annealed at 500 °Cfor 1 h showed a marked change. These films were found to oxidize significantly. TiN
films at 500 °Cchanged to a purple brown color. The alloy films of Ti—Al and Ti—Zr and carbonitride films were found to be quite stable up to 500 °C, the highest temperature used in this study. 3.5. Corrosion studies Corrosion studies were carried out by exposing the films to concentrated HNO3 fumes for 72 h and to a salt spray at room temperature for
72 h. The SEM examination of TiN and zirconium carbonitride films before and after exposure showed that there was no noticeable difference in the film quality. This indicates that these films are quite stable to corrosion by concentrated HNO3 and salt spray. The color coordinates were also checked before and after exposure. No noticeable differences in the L*, a* and b* values were observed. This is expected as the cathodic arc deposited films are very dense and have a very fine-grain equiaxed structure [7].
6 5-
0 0~N005
~ — —
—*-— ~—
— —
~
a~
—
~ —
—
40
~~iC00~No.g~ V’Zrn
30
—
ZrC015N0~5 1
b
20
-4.-—— 10
-
I 100
I 200
300
I 400
TEMPERATUREICI
3
--
TiN
TIN1
-
2 =
835
TIC
-
I 500 ——
-—b
ZrN
Fig. 3. Effect of annealing on color coordinates of various hard films.
4. Conclusions It was shown that the cathodic arc deposition process is a viable process for the deposition of hard coatings for decorative applications. Furthermore, cathodic arc deposited films show excellent wear, corrosion resistance and film quality that is reproducible to match various gold colors. Acknowledgments The author wishes to express his thanks to Mr. Randy Cunningham for his help in the preparation of these samples and to Ms. Norma Vincenzetti for her help in preparing the manuscript.
836
References 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
A. Mumtaz and W. H. Class, J. Vac. Sci. Technol., 20 (1982) 345. S. Schiller, G. Beister and W. Sieber, Thin Solid Films, 111 (1984) 259. A. J. Perry, J. Vac. Sci. Technol. A, 4 (6) (1986) 2670. H. Randhawa, 7th mt. Conf. on Thin Films, New Delhi, India, December 7- 11, 1987, in Thin Solid Films, 167 (1988). I. Aoki, R. Fukutome and Y. Enomoto, Thin Solid Films, 130 (1985) 253. W. D. Sproul, Thin Solid Films, 107 (1983) 141. H. Randhawa, P. C. Johnson and R. Cunningham, J. Vac. Sci. Technol., July (1988). H. Randhawa, J. Vac. Sci. Technol. Technical Review, Surf. Coat. Technol., 33 (1987) 53. A. J. Perry, J. Vac. Sci. Technol. A, 4 (6) (1986) 2674. H. Randhawa, Thin Solid Films, 203 (1987) 159. A. Snaper, U.S. Patent, 3,625,848, December 7, 1971. H. Haessler and H. Freller, Thin Solid Films, 67(1987) 153. A. J. Perry and J. Schoenes, Vacuum, 36 (1984) 149. B. Karlsson, J. E. Sundgren and B. 0. Johansson, Thin Solid Films, 87 (1982) 181. w. D. Munz, personal communication.
829
HARD COATINGS FOR DECORATIVE APPLICATIONS* H. RANDHAWA Vac-Tec Systems, Inc., 6101 Lookout Road, Boulder, CO 80301 (U.S.A.) (Received April 11, 1988)
Summary Reactively deposited films of TiN and ZrN are of great interest as decorative coatings and in architectural glass applications. Traditional methods of film deposition have posed problems related to available deposition rates, film quality and color control. The cathodic arc plasma deposition process offers an alternative to deposit such films with good uniformity, film quality and color control. This paper deals with hard coatings for decorative applications deposited using the cathodic arc process. The films of TiN, ZrN, HfN, TiA1N and TiZrN are characterized in terms of structure and morphology, colorimetric and optical reflectance, hardness, wear resistance and corrosion resistance. It is demonstrated that by adjusting process conditions, doping with carbon and/or alloying with other elements it is possible to adjust coating colors over a wide range and to simulate closely a range of gold colors. The cathodic arc therefore provides a significant alternative to existing techniques for a wide range of decorative applications. 1. Introduction The group IVb nitrides with their gold-like colors have generated a great deal of interest [1 5] as economical, hard, scratch-resistant decorative coatings. With the recent developments in plasma enhanced physical vapor deposition processes, hard films of negligible self roughness have been made [6, 7] at temperatures as low as 300 °Con substrates such as stainless steel. Earlier studies [1, 3] on the color of TiN films deposited by ion plating or sputtering indicated that the films varied with the deposition conditions, method of preparation, etc. A very careful control of deposition parameters, such as deposition rate, nitrogen partial pressure, substrate temperature, etc., was needed to ensure reproducibility of color and consistency. The cathodic arc plasma deposition process was considered to be unsuitable [8] for decorative applications until recently, owing to the presence of macroparticles in the film. The latest developments [4, 8] involving the -
*paper presented at the 15th International Conference on Metallurgical Coatings, San Diego, CA, U.S.A., April 11 - 15, 1988. 0257-8972/88/$3.50
© Elsevier Sequoia/Printed in The Netherlands
830
elimination of macroparticles in the cathodic arc process have provided a significant alternative to existing techniques for a wide range of decorative applications. The cathodic arc process also offers a great deal of flexibility; e.g. the control of deposition parameters is less stringent than in magnetron sputtering or ion plating (the magnetron sputtering and ion plating processes require control of the partial pressure of the reactive gas as compared with control of the total pressure in the chamber in the cathodic arc process) and the deposition temperature can be adjusted and controlled over a much wider range thus enabling substrates such as zinc castings, brass and even plastics to be coated. 2. Experimental details The films investigated in this study were prepared on ASTM 304 lapped stainless steel samples (size, 1 in X 2 in) using an ATC 400 production-type cathodic arc plasma system. The system is described in detail elsewhere [4]. A substrate to source distance of 10 in was used. A reactive gas of nitrogen in the case of nitrides and acetylene in the case of carbides was used. The incorporation of carbon in the nitride films was achieved by using a mixture of nitrogen and acetylene gas. The film composition was varied by varying the gas flow rates of the reactive gases at a constant metal evaporation rate and constant substrate temperature of 300 °C.Typical deposition rates were 0.3 j.tmmTorr. min1. The total pressure in the system was varied in the range 2 -10 The films were analyzed for microhardness using a Knoop microhardness tester at a load of 20 gf. The compositions of the films were studied using scanning Auger microprobe analysis (SAM) and electron spectroscopy for chemical analysis (ESCA). The color coordinates L*, a* and b* were measured using a Hunter Labscan II with a d/8 geometry and D65 illumination. The heat treatment applied here was based on earlier observations [9] that an expanded and distorted crystal lattice contracts towards the equilibrium value during annealing at elevated temperatures of up to 500 °Cin air. Above this temperature, TiN and ZrN films were found to discolor due to oxidation. The effect of aging on color was studied by storing the samples in air at room temperature for a period of 6 months. The effect of corrosion on color was studied by exposing the coated samples to fuming HNO 3 for 72 h and salt spray for 72 h at room temperature. This simulates the exposure to human skin for several years. 3. Results and discussion 3.1. Deposition process
The deposition of the films was carried out using a cathodic arc plasma deposition process. The process is described in detail elsewhere [10]. Con-
831
(b)
(a)
Fig. 1. Scanning electron micrographs of TiN films obtained by (a) a conventional arc process and (b) a modified cathodic arc process.
ventional vacuum arc processes [11, 121 suffer from the presence of droplets in the deposited films and are thus considered to be unsuitable for decorative applications. In this study, a modified cathodic arc process was used where the droplets are eliminated in the coating. Figure 1 shows a scanning electron micrograph of TiN films obtained using a conventional vacuum arc process and the present modified process. It can be seen that the droplets are eliminated in the TiN film produced using the modified process. This modified arc process is described in detail in a separate publication [4]. 3.2. Color: as-deposited films
The color was measured with a Hunter Labscan II using D65 illumination and d/8 geometry. The data for TiN and ZrN are shown in Table 1 in the as-deposited condition. It was found that in both TiN and ZrN the a* TABLE 1 Color coordinates of various as-deposited hard films Sample
Composition
L*
a~’
1 2
TiN TiC
77-80
3 4
0~N095 TiC010N0~ TiC0
76 - 79 71-75 66 - 69
5.5 - 8 8.5-11 ii - 16
30 - 33 23-28 21 - 22
5 6 7
ZrN ZrC010N0~ ZrC015N085
86-89 81 - 84 79-81
—3-—i —i -—0.4 0-3
23-25 26 - 29 17-19
8 9
Gold,i0karat Gold, 24 karat (pure)
81-86 88 - 91
—1.6-i —37 - 1
19-30 27 - 34
2-5
b* 33-37
832
(redness) and b* (yellowness) parameters varied with the nitrogen level. Simlar results were anticipated for TiN films by earlier workers [2, 3]. TiN films obtained using the ion plating process possess a color that is greener than the standard color of yellow gold. In contrast, sputtered films are slightly brownish in appearance giving more redness in the film. This has been attributed to the columnar microstructure and to the slightly overnitrided films typically obtained from sputtering. It was found in this study that the color of TiN deposited by the cathodic arc process was closer to yellow gold. This is illustrated in Table 2. Furthermore, it was found that with the nitrogen pressure in the range 5 10 mTorr the color of the TiN films was fairly consistent in terms of L*, a* and b* values, thus giving a wider range of operating pressures and enhanced reproducibility. It was also found that the substrate temperature above 250 °Chad no noticeable effect on the color. Similar studies carried out using magnetron sputtering show a variation in the color of the film due to a variation in substrate temperature [15]. -
TABLE 2 Comparison of color coordinates of TiN films obtained by various deposition processes Process
L*
Composition
Sputtering Ion plating
75 74
-
77 80
3- 8 0.5 - 10
25 20
-
35 30
15 TiN TiN~
Cathodic arc
77
-
80
2-5
33
-
37
TiN
05
By introducing carbon into the TiN and ZrN films it was found that the color could be altered significantly. The introduction of carbon was achieved by using acetylene gas in the mixture. Table 1 lists the relative L*, a* and be values with increasing concentrations of carbon in the films. As is clear from the values listed in Table 1, a pronounced shift towards the red results from the incorporation of increasing amounts of carbon in the films. Thus carbon contents can be adjusted to match desirable gold colors. On alloying titanium with suitable elements, such as zirconium and aluminum, it was observed that the a* and b* values of the corresponding nitrides could be suitably matched to standard 10K gold or 24K gold colors. These results have been reported previously [7].
The color of the nitrides and their metallic luster are due to electron transitions in the energy band. It is these electrons which, on relaxation, emit yellow gold light and their number is a measure of brightness. The introduction of carbon into TiN or ZrN films reduces the number of energy states to which electrons can be excited, and thus the brightness is lowered with increasing contents of carbon as shown in Table 2. Similar results have
been reported previously in the case of oxygen incorporation [1]. The effects on the color of the group IVb nitrides have been described previously in terms of a simple qualitative ionic model.
833
3.3. Microhardness The microhardness measurements were carried out on various nitrides and carbonitrides using a Knoop indentor and a load of 20 gf. A film thickness of 3 pm was used. Results of these measurements are shown in Table 3. As is clear from this table all the films have microhardnesses in the range 2400 3450 kgf m2, and thus are quite hard. The films were also found to be very wear resistant compared with gold films. In a typical wear study involving tumbling the coated parts in an abrasive medium of metal filings, gold film with a thickness of approximately 1 pm was worn in less than 10 s whereas for most of these hard coatings several hours were required for comparable wear. -
TABLE 3 Color and microhardness of films Composition
Color
Hardness (kgf m2) (15 gf)
TiN ZrN HfN TiC~Ni_~(x 0.05 -50) ZrC~Ni_~ (x = 0.05 - 20) Ti~Ali_~N(x = 0.1 -70) Ti~Zri_~N(x = 20 -80)
Golden yellow Golden green Yellow—green Reddish gold—brown Golden Golden, brown—black Golden
2400 3200 2750 2450-2900 3250 - 3450 2400 -2900 2400 -3250
3.4. Aging and annealing effects Mononitrides of titanium, zirconium and hafnium were found to age significantly in terms of color. These films tend to darken with time. Figure 2 shows the effect of aging on the color coordinates for TiN, ZrN, carbonitrides and TiZrN over a period of 6 months. It is interesting to note that most of the aging occurs in the first several days and then it tends to slow down. The results on the carbonitride films and the films of alloy nitrides are included. From these results it can be seen that carbonitrides and alloy nitride films hardly age at all compared with minor nitrides. Perry [9], using a simple ionic model, attributed the aging effects in TiN and H!N films deposited by ion plating to lattice contraction to equilibrium values. However, there are also other surface-induced effects, such as surface film oxidation due to exposure to air, that are only surface related and not a bulk phenomenon. Further studies to understand this behavior are currently underway. The effect of annealing was investigated by heat treating the films at temperatures of 100, 200, 300, 400 and 500 °Cfor a fixed period of 1 h in air. The color coordinates were monitored before and after annealing. The results are shown in Fig. 3. There are no significant effects on color in the various films up to 300 °C. However, the color coordinates of TiN film
834 5
—
4
-$j
-
T~N I
I
I
~
~
40 30
ZrC •
1~N005
a
A_
A
0
I
2 TIME MonthsI
5
6
Ti0~Zr0 N 1
x
s ~
x
n
i.
~
x ZrN
-2
-3
Fig. 2. Color coordinates of various hard films.
annealed at 400 °Cfor 1 h and ZrN film annealed at 500 °Cfor 1 h showed a marked change. These films were found to oxidize significantly. TiN
films at 500 °Cchanged to a purple brown color. The alloy films of Ti—Al and Ti—Zr and carbonitride films were found to be quite stable up to 500 °C, the highest temperature used in this study. 3.5. Corrosion studies Corrosion studies were carried out by exposing the films to concentrated HNO3 fumes for 72 h and to a salt spray at room temperature for
72 h. The SEM examination of TiN and zirconium carbonitride films before and after exposure showed that there was no noticeable difference in the film quality. This indicates that these films are quite stable to corrosion by concentrated HNO3 and salt spray. The color coordinates were also checked before and after exposure. No noticeable differences in the L*, a* and b* values were observed. This is expected as the cathodic arc deposited films are very dense and have a very fine-grain equiaxed structure [7].
6 5-
0 0~N005
~ — —
—*-— ~—
— —
~
a~
—
~ —
—
40
~~iC00~No.g~ V’Zrn
30
—
ZrC015N0~5 1
b
20
-4.-—— 10
-
I 100
I 200
300
I 400
TEMPERATUREICI
3
--
TiN
TIN1
-
2 =
835
TIC
-
I 500 ——
-—b
ZrN
Fig. 3. Effect of annealing on color coordinates of various hard films.
4. Conclusions It was shown that the cathodic arc deposition process is a viable process for the deposition of hard coatings for decorative applications. Furthermore, cathodic arc deposited films show excellent wear, corrosion resistance and film quality that is reproducible to match various gold colors. Acknowledgments The author wishes to express his thanks to Mr. Randy Cunningham for his help in the preparation of these samples and to Ms. Norma Vincenzetti for her help in preparing the manuscript.
836
References 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
A. Mumtaz and W. H. Class, J. Vac. Sci. Technol., 20 (1982) 345. S. Schiller, G. Beister and W. Sieber, Thin Solid Films, 111 (1984) 259. A. J. Perry, J. Vac. Sci. Technol. A, 4 (6) (1986) 2670. H. Randhawa, 7th mt. Conf. on Thin Films, New Delhi, India, December 7- 11, 1987, in Thin Solid Films, 167 (1988). I. Aoki, R. Fukutome and Y. Enomoto, Thin Solid Films, 130 (1985) 253. W. D. Sproul, Thin Solid Films, 107 (1983) 141. H. Randhawa, P. C. Johnson and R. Cunningham, J. Vac. Sci. Technol., July (1988). H. Randhawa, J. Vac. Sci. Technol. Technical Review, Surf. Coat. Technol., 33 (1987) 53. A. J. Perry, J. Vac. Sci. Technol. A, 4 (6) (1986) 2674. H. Randhawa, Thin Solid Films, 203 (1987) 159. A. Snaper, U.S. Patent, 3,625,848, December 7, 1971. H. Haessler and H. Freller, Thin Solid Films, 67(1987) 153. A. J. Perry and J. Schoenes, Vacuum, 36 (1984) 149. B. Karlsson, J. E. Sundgren and B. 0. Johansson, Thin Solid Films, 87 (1982) 181. w. D. Munz, personal communication.