440 Prakt. Met. Sonderband 38 (2006) 
the absorbance at 600 nm was 0.050. Substrates were placed in well plates and sterilized by 3. 
irradiation with UV light for a period of 30 minutes. A small quantity (3 mL) of the appropriate 
bacterial solution was added to each well and the well plates were allowed to incubate at He 
37°C for 48 and 72 hours. Four substrates per bacterial strain per incubation period were na 
produced to carry out this experiment. After incubation, the bacterial solution was removed the 
from each well and its absorbance was measured at 600 nm. The substrates were then vo 
removed, rinsed thoroughly but gently, and stained for a period of 10 minutes with 1% crystal Th 
violet solution. The stained substrates were then soaked in 3 mL of dimethyl sulfoxide for a wi 
period of 10 min. and the absorbance of these solutions was subsequently measured. 
3. RESULTS 
3.1 Structural Properties 
The structural and chemical properties of ZrN-Ag films were investigated in our previous 
article.’ The following is a brief summary of the main results reported in that article. Films 
grown with a bias voltage of -70 V exhibit strong (200) and (111) preferred orientations. The 
films became more textured with the application of a larger substrate bias and only the (111) 
preferred orientation was observed for the films grown with a substrate bias of -160 V and - 
190 V. A representative plan-view TEM micrograph for sample S2 is shown in Fig. 1. This 
bright field micrograph shows that the films consisted of nanometric dark grains (Ag we. 
precipitates) that are distributed evenly throughout a light ZrN matrix. Diffraction rings 
corresponding to the cubic structure of ZrN (a = 0.4578 nm) were present in the selected area T 
electron diffraction (SAED) pattern. Nevertheless, all diffraction rings were very broad W 
because of the small size of the ZrN clusters with the diffraction ring corresponding to the wi 
(111) planes of ZrN (d = 0.4578 nm) being the most intense be 
th 
re 
ac 
Tt 
In 
Ci 
M 
el 
m 
ir 
__— 100 nm— ) 
Figure 1: TEM Micrograph of sample S2 FE