Reaction Moulding of Metal and Ceramic Powders

Abstract

A processing route for fabrication of products from hard metal and ceramic powders is described in which a reactive monomer such as ethylcyanoacrylate is used as carrier and binder with the opportunity of recovery through thermal depolymerization. A feasibility study has examined some of the main technical points including monomer–powder reactivity and rheology, debinding rates and compact green density. The stability of ethylcyanoacrylate with various powder volume fractions of silicon nitride and 316L stainless steel has been examined, with p‐toluenesulphonic acid used as polymerization inhibitor, and it was found that mixes with higher powder volume fractions required higher levels of inhibitor. Assessment of the flow behaviour of several of the compositions showed them to be significantly non‐Newtonian and the high viscosity of blends with a high loading of stainless steel suggests some premature polymerization. Measurement of green density of polymerized compacts demonstrated that high packing efficiency could be achieved. Thermogravimetry showed that rates of binder loss depended upon sample size and powder thermal conductivity.

On the Wear Behavior of Cyanoacrylate in Presence of Nano-Sized SiO<sub>2</sub>

“…814725, Merck) was utilized. Neutralization should take place before polymerization [28,43] and for this purpose caffeine (catalogue No. 119164, Merck) was used in the current research.…”

Role of nano‐size SiO2 additive on the thermal behavior of cyanoacrylate nanocomposite

“…Any practical, weak‐electron‐donor base, such as moisture on the surface of a substrate, can trigger the polymerization reaction [7, 8]. Basic chemicals such as sodium carbonate, phosphates, amines, caffeine, or pyridine can be used to neutralize the stabilizer and so accelerate polymerization [2, 9, 10].…”