Effects Of Addition Of C And Ta Elements On The Properties Of The Amorphous Alloy Ni-Cr-Nb-P-B

Based on the study of Ni-based amorphous alloy,this paper chooses the alloy systems Ni-Cr-Nb-P-B-C and Ni-Cr-Nb-P-B-Ta as the research object.This experiment shows the method of copper mold casting in the high vacuum induction melting and casting system to obtain the alloy rod.More specifically,it analyzes whether the alloy is amorphous or not by means of XRD whose type is Rigaku D max-2500 PC;it tests the samples' thermal stability by DSC;in addition,it detects the mechanical properties of the alloy and the corrosion resistance of the amorphous ribbon by using the ways of compression test and Electrochemical Workstation respectively.What should be noted is that all the experiments have been done in the room temperature,and the corrosion situations are 3.5%wtNaCl?1mol/LHCl?1mol/LH₂SO₄?1mol/LHNO₃?1mol/LNaOH.Last but not the least,this experiment also studies the fracture morphology of the compressed alloy and the morphology of the corrosive amorphous ribbon by using SEM.The studies show that in the system of Ni-Cr-Nb-P-B-C,the suitable addition of C element can improve the glass forming ability of Ni_68.6Cr_8.7Nb₃P_?16.5-x?B_3.2C_x;the alloy Ni-Cr-Nb-P-B-C can obtain the amorphous rod whose diameter is 2mm when x is 0.5.The suitable addition of C element improves the thermal stability of Ni-based amorphous alloy.Moreover,the supercooled liquid region can reach up to 44.3K when x is 0.5 and the diameter is 1.5mm,compared with the region in the situation where x is0 and the diameter is 1.5mm,it increases 20.2K.And with the increase of C element,the compression property decreases gradually.With the increasing of C amount,the amorphous ribbon corrosion resistance property increases gradually in 3.5%wt NaCl?1mol/L HCl?1mol/LH₂SO₄?1mol/LHNO₃?1mol/L NaOH solutions,and this system shows better corrosion resistance in acid solutions.Besides,in the system of Ni-Cr-Nb-P-B-Ta,the alloy rod becomes complete amorphous with a diameter of1.5mm when x is 0.5,while when x is in other conditions,the alloy precipitates the crystalline phase.The appropriate addition of Ta element improves the thermal stability of Ni-based amorphous alloy,and it gets the best thermal stability when x is 0.5,whosesupercooled liquid region's width is 40.6K,and compared with the alloy rod without Ta element,the width of supercooled liquid region increases 16.5K,which shows that it processes better thermal stability.While afterwards,the thermal stability begins to decrease.And with the increase of Ta element,the compression property of the alloy rod increases first and then decreases,and when x is 0.5,its compression property is the best.In addition,with the increase of Ta amount,the corrosion resistance of Ni-based amorphous ribbon gradually enhances under the condition of 3.5%wtNaCl?1mol/LHCl?1mol/LH₂SO₄?1mol/LHNO₃?1mol/LNa OH solutions,besides the system shows better corrosion resistance in the acid solutions.