As to 18%Cr, 18%Cr-1, 2%Mo, 23%Cr and 23%Cr-1%Mo stainless steel powders produced by the water-atomization, an investigation was made about the influence of Mo addition on the corrosion resistance of the sintered steels.
Results are summarized as follows.
(1) In the nitric acid, no influence of Mo addition is observed in 18%Cr and 23%Cr sintered steel.
(2) The influence of Mo on the sulfuric and hydrochloric acid corrosion is remarkable. When the sintered density is 6.5 g/cm3, the corrosion rate in 5% sulfuric acid of the sintered steels containing Mo decreases with the relation of 1/4Mo1.2+1 to that of the steels containing no Mo.
(3) If the sulfuric and hydrochloric corrosion rate of 18%Cr and 18%Cr-2%Mo sintered steels is compared with the annealed cast steel, logarithm of the corrosion rate of 18%Cr-2%Mo can be expressed as a linear equation of the sintered density, while in the case of 18%Cr the rate of fully dense sintered steel is bigger than that of annealed cast steel.
(4) In these corrosion, the dropping of powder particle from the surface of 18%Cr sintered steel is observed. But, this phenomenon is not observed in the 18%Cr-2%Mo sintered steel.