The Preparation,Organization And Properties Of High Si-Fe Alloys With Goss Texture

Fe-6.5wt.%Si alloy has excellent comprehensive magnetic properties,such as low iron loss,high permeability and infinitesimal magnetostriction coefficient,so it is the best soft magnetic material to make the core of transformer.However,there is still no mature preparation technology at home and abroad.At present,only the CVD method in Japan is able to implement small-scale production,but it also has disadvantages such as high energy consumption,corroding equipment and environment pollution.In addition,it has been pointed out that the high-frequency iron loss of high Si-Fe alloy is lower when the silicon content is higher than 6.5wt.%.And the iron loss of high Si-Fe alloy with gradient distribution of silicon content is lower.Therefore,these possible conclusions are investigated in this experiment.In this experiment,solid power embedding method is used to siliconize on the finished plate of Fe-3.0wt.%Si grain oriented steel.Compared with the CVD method,the siliconizing temperature is low and the content of corrosive halide is very low,and solid power embedding method can stably prepare the siliconizing layer with smooth surface,densed internal structure and well-bonded with the matrix.By controlling the siliconizing time,the samples with different thickness of siliconizing layer could be obtained.Then the samples of different siliconizing time proceed with the homogenizing diffusion annealing,and got the high Si-Fe alloy with gradient distribution of silicon content and uniform silicon content.Finally,there were the hardness test and magnetic properties test for three kind of samples,and clarified the relationships between microstructure,chemical composition,phase and properties.Select the typical samples for texture and tensile test,thus this experiment was able to determine the evolution rule of texture and compare the tensile properties of three samples.The main conclusions are as follows:(1)The siliconzing samples with siliconzing layers of different thickness could be obtained after the solid siliconizing treatment for 10?20min at 800?.The surface silicon content increased with the increase of siliconzing time,and Fe3Si phase and FeSi phase were formed on the surface.(2)Finish the homogenizing diffusion annealing for siliconizing samples at 1050?.When the holding time was 1 h,the gradient high Si-Fe alloy was obtained,and the silicon content continuously decreased from the surface to the center.When the holding time was 2 h,the high Si-Fe alloy with uniform silicon content was obtained.With the increase of surface silicon content,the low-frequency iron loss of grain-oriented high Si-Fe alloy was higher than that of the original sample,but the medium-frequency iron loss significantly reduced.In addition,the magnetic induction intensity decreased slightly.(3)Compared with the siliconizing sample and the high Si-Fe alloy of uniform silicon content,the iron loss of gradient high Si-Fe alloy was the lowest at medium and high frequencies.When the surface silicon content was 12.3wt.%,the iron loss of gradient high silicon steel was relatively low,and the reduction of iron loss was above 90%,up to 97.3%..(4)The hardness of grain-oriented high si-fe alloy increased with the increase of silicon content,and the hardness of FeSi phase was higher than that of Fe3Si phase.After diffusion annealing for 1 h,the surface hardness of the sample decreased and the core hardness increased.After diffusion annealing for 2 h,the hardness remained basically unchanged along the depth.(5)After solid siliconizing and diffusion annealing,the Goss texture had no change and was able to be retained.Compared with the original sample,the siliconizing sample showed the brittle fracture.After diffusion annealing,the sample had certain plasticity and presented plastic fracture.