Search

A series of wear and flame resistant polyamide 6 (PA6) composites were prepared using glass fiber (GF) and talc (T) as reinforcer, polytetrafluoroethylene (PTFE) and graphite (Gr) as solid lubricants, red phosphorus (RP) and zinc borate (ZB) as flame retardant. The tribological property, mechanical property, flame retardant property and the flame retardant mechanism were investigated. The tests show that the formula of the wear resistant PA6 composite (WRPA 6) is PA6/GF/T/PTFE/Gr in the ratio of 100/15/5/10/5 by mass. Because this composite exhibits the lowest friction coefficient (0.1429) and no wear mass loss, the introduction of RP and ZB can increase the flame resistance of WRPA6, and the synergistic effect of RP and ZB is obtained. Detailedly, the composite with 4 parts of ZB and 12 parts of RP shows the best flame retardant property, achieving the highest limiting oxygen index (LOI) (30.2 vol%) and a UL94 V-0 rating, and the flame retardant mechanisms may be gas phase along with condense phase mechanism.

In the present work, N2, N2 + H2, Ar and Ar + H2, were used as the sintering atmosphere of Metal Injection Molded 316L stainless steel respectively. The influences of the sintering atmospheres on C, O, N contents of the sintered specimens, sintered density, grain morphology and mechanical properties were investigated. The results show that C, O, N contents of the sintered specimens can be controlled in permitted low values. The ultimate tensile strength and elongation of the specimen sintered in N2 + H2 atmosphere are 765 MPa and 32% respectively. Using Ar and Ar + H2 as the sintering atmosphere, the density of the sintered specimens is 98% of the theoretical density; the pores are uniformly distributed as small spherical shape and the grain size is about 50 µm. The mechanical properties of the specimen, i. e. ultimate tensile strength 630 MPa, yield strength 280 MPa, elongation 52%, HRB 71, are much better than those of the American Metal Powder Industries Federation (MPIF) 35 Standard after being sintered in Ar + H2.