Binder Design Of Self-fluxing Alloy Powder

To solve the powder waste problem of the traditional hot spray-welding technique of coating process, the paper introduces the theory of binder. The powder were Ni60 and Fe30. The process includes two steps. And the first step is pre-coating samples by mixture of binders and self-fluxing alloy powders, and the second step is remelting the former by intermediate frequency induction remelting heating. As result wear-resisting and corrosion-resistance coats are approached. At last, the kind, composition, propertie and binding principle were researched. According to the varieties of binder, the binder concentration, mixed-powder proportion and drying-temperature are determined. The optimal group is 2%-C with 7%-mixed-powder proportion and 140℃-drying-temperature. It is indicated by the hardness measurement, on the Ni60 coat, pre-bonding coats improve the hardness by three times, equal to the effect of traditional hot spray-welding technique. However, the porosity is lower, which manifasts the binder advances the compactness of coatings. The hardness of Fe30 is increased by 1.5-fold. From the coating organization morphologies, the Ni60-coat owns homogeneous organizations with bright mitrx and black hard phase, including little holes and oxides, no big porosity and crack.,including Ni3B,,Ni2B,Cr2B,,CrB,,Ni3Si,,Fe3C,Cr7C3,M23C6(Cr23C6,(Fe,Ni)23C6). So the binder is able to change the existential state of hard phases, from the original aggregated distribution to dispersoid distribution, and plays the effect of dispersion reinforcement. The binder used in Fe30-coats improves the fluxility and the lubrication angle of self-fluxing alloy powders, in which there are some carbide, chrome carbide, and boron hydrates . The hardnesses and melting points of those kinds of intermetallic compound are very high. In addition, the pre-bonding coats have high performance of wear-resisting and suitable rubbing pairs, as well as better corrosion-resistance.