Study Of Effect Of Substrate Temperature On High Temperature Stability Of Ni And NiAl Infrared Reflectors

Ni and NiAl infrared reflectors were prepared by ion beam assisted deposition at different substrate temperatures. The effect of substrate temperature on the phase structure, surface morphology, reflectance and high temperature stability were investigated by X-ray diffraction, scanning electron microscope, dual mode 3D profilometer and ultraviolet-visible-near infrared spectrometer. The results were listed as follows:(1) Substrate temperature has a great effect on the phase structure, surface morphology, infrared reflectance and high temperature stability of Ni infrared reflector. Grains of Ni infrared reflector deposited at 100 ℃ grow along(220) crystal plane of preferred orientation highly; its surface is the most smooth and surface roughness is the smallest; its reflectivity is highest in infrared wavelength range. The Ni infrared reflector deposited at 300 ℃ exhibits the most stable phase structure,surface morphology and reflectance.(2) A phenomenon that Ni/Al atomic ratio in the sample increases with sputtering power when Ni Al infrared reflector was deposited by Ni-Al alloy target was found.The reason is showed as follows: energy of Ar+ reaching the surface of target increases as sputtering power increases. As a result, the temperature of target surface will rise and there will be more evaporation of Al. Ultimately, Al and Ni contents in the target and film deposited will decrease and increase respectively. The relationships between Ni/Al atomic ratio in the film and SNi-Al/SAl or SNi/SAl in effective sputtering area were studied when we used the Ni-Al/Al and Ni/Al inlay targets respectively.The value of Ni/Al atomic ratio in the film increases as the value of SNi-Al/SAl or SNi/SAl in effective sputtering area increases.(3) Grains of NiAl infrared reflector deposited at 25 ℃ grow without preferred orientation; its surface roughness is highest and reflectivity is smallest in infrared wavelength range. Grains of NiAl infrared reflector deposited at 300 ℃ grow along(110) crystal plane of preferred orientation highly; its surface roughness is smallestand reflectivity is highest in infrared wavelength range. The NiAl infrared reflector deposited in 300 ℃ exhibits the most stable phase structure, surface morphology and reflectance.