1998 Volume 16 Issue 1 Pages 25-34
The effects of spary conditions on the properties of HVOF Cr3C2-25%NiCr coatings are investigated using parameters of oxygen flow, fuel gas flow and spray distance based on orthogonal regression experimental design method. The propane gas is used as a fuel gas. The properties of the coatings are characterized by adhesive strength, hardness, abrasive wear and erosion tests. The abrasive wear is estimated using dry-sand rubber wheel tester. The relationships between the properties of the coatings are examined. The results show clearly that the properties of HVOF Cr3C2-25%NiCr coatings are greatly influenced by gas flows of both oxygen and propane during HVOF. The regression formulas with 2nd power between the properties and spray parameters are established. It is found that the optimized coating with good abrasive wear and erosion resistances can be obtained with adequate gas flows of both oxygen and propane. The examination of experimental results showed that there is no evident relation between hardness and wear resistance for HVOF Cr3C2-25%NiCr coatings. On the other hand, it is found that there exist evidently the correlation between coating abrasive wear and erosion wear at low impact angle.
