材料期刊网

Diamond-like carbon ( DLC ) -films were successfully deposited on Ti- 50.8at% Ni using plasma based ion implantation (PBII) technique. The influence of the pulsed negative bias voltage applied to the substrate from 12 kV to 40 kV on the microstructure, nano- indentation hardness and Young' s modulus, the surface characteristics and corrosion resistant property as well as hemocompatibility were investigated. The experimental results showed that C 1 s peak depended heavily on the bias voltage. With the increase of bias voltage , the ratio of sp2 / sp3 -first decreased, renching a minimum value at 20 kV, and then increased. The DLC coating deposited at20 kV showed the highest hardness and elastic modulus values as a result of lower sp2 / sp3 ratio. The RMS values first decreased from 7.202 nm( 12 kV) to 5.279 nm(20 kV), and then increased to 11.449 nm(30 kV) and7.060 nm(40 kV). The uncoated TiNi alloy showed severe pitting corrosion, due to the presence of Cl-ions in the solution. On the contrary, the DLC coated sample showed very little pitting corrosion and behaved better corrosion resistant property especially for the specimens deposited at 20 kV bias voltages. The platelet adhesion test show that the hemocompatibility of DLC coated TiNi alloy is much better than that of bare TiNi alloy, and the hemocompatibility performauce of DLC coated TiNi alloy deposited at 20 kV is superior to that of other coated specimens.