Research On High Temperature Corrosion Property Of Ni-based Alloy Prepared By Laser Cladding

Biomass energy is widely used in biomass power generation as an alternative energy.The high proportion of alkali metals and chloride in the biomass can cause severe high temperature chloride corrosion under a certain temperature.Commonly used boilers'heating surfaces of the metal materials can not be qualified for the internal environment of biomass boilers,while high-temperature erosion problems exist in some parts of the biomass boilers are also the main reasons for the failure of heat exchanger materials.In order to improve the corrosion resistance of the heating surfaces,use C22 powder to make C22 coating by laser cladding.At the same time,considering that the soft Hastelloy could not prevent the problem of high temperature erosion,so we selected Ni-base alloy Ni60,which is relatively wear-resistant,is blended in 10%,20%into the heat transfer surfaces cladding layer.In this paper,the laser cladding is used to make C22,and 10%,20%Ni60 blended C22 cladding layer,the hardness test,wear test and high temperature chloride test on three kinds of materials are carried out.The wear resistance of the material was measured by using a Vickers hardness tester at a load of 500 g,and the wear test was carried out at 240 r/min and T=2000 using an abrasive wear tester for 5 cycles.Based on the relationship between the hardness and the weight loss of the material,the wear resistance of the cladding layer was analyzed.The experience result show that add Ni60 to C22 making laser cladding generated CrB2,Fe8B.It help to improve the wear resistance of material.High temperature corrosion tests were carried out at 550?,600 ?,650? and 700?,respectively,under different ratios of NaCl and KCl were used to simulate the corrosive environment of forestry and agricultural biomass.Each state of the sample into the furnace corrosion 12h,after cleaning up the surface corrosion products,the next corrosion time increased 12h each time,a total of 8 cycles.The corrosion resistance of the materials is measured by measuring the weight loss of the materials.After the test,the corrosion products composition was analyzed by XRD,and the surface and the cross section of the samples were observed by scanning electron microscopy(SEM)and energy dispersive spectroscopy(EDS).Finally,the corrosion results are described in details,and the corrosion mechanism of the samples is analyzed.The experience find that the corrosion resistance decline after adding Ni60 material.It because of CrZO3 gradually disappear and B oxide accelerating the flow of the molten salt in liquid at high temperature.