VANADIUM CARBIDE FILMS PRODUCED BY PLASMA-ASSISTED METAL-ORGANIC CHEMICAL-VAPOR-DEPOSITION

Vanadium carbide films as wear-resistant coatings produced by salt bat h immersion at high temperatures have found wide technological applica tion in manufacturing industries. In order to reduce the substrate tem perature, the deposition of VC-films by plasma-assisted chemical vapou r deposition using a metal-organic compound as precursor was investiga ted. Bis(cyclopentadienyl)-vanadium, a purple solid compound showing a sufficient sublimation rate at relatively low evaporator temperatures , was used together with hydrogen and argon to deposite VC-films in a d.c. glow discharge. As one of the most important parameters the subst rate temperature was varied from 200-degrees-C to 400-degrees-C. The c ompound decomposed into films and gaseous by-products like C5H6 and ot her hydrocarbons which could be detected by quadrupole mass spectromet er. The deposition efficiency of the coatings was almost independent o f the substrate temperature. It was established by means of EDX and XR D that cubic vanadium carbide coatings were obtained. The morphology o f these layers was examined by scanning electron microscopy. In the en tire temperature range dense, polycrystalline layers were created, who se hardness measured between 2200-3300 HV. With the increase of the su bstrate temperature the adhesive strength of the coatings increased, t oo.