Preparation And Characterization Of Novel Lithium Sodium Potassium Niobate Biological Piezoelectric Ceramics

With the development of biotechnology and the pursuit of health,people has higher demand on the properties of biological ceramic materials.Biological piezoelectric ceramic materials exhibit greater advantages in biocompatibility,non-toxicity,chemical stability,repair,repair rate,etc.So it has broad application prospects in the field of bone repair and substitute materials.Novel lithium sodium potassium niobate?LNK?biological piezoelectric ceramic is a kind of Li-doped sodium potassium niobate based ceramic.It has excellent piezoelectric properties,which can promote the growth of cells and repair effectively in the organism.Hydroxyapatite?HA?is a major component of human bones,which has excellent biocompatibility.Porous materials have large specific surface area,pore structure is beneficial to the entry of nutrient substance and cells in the human body to accelerate the repair rate.In this thesis,biological ceramics were designed to be porous,composite and piezoelectric materials.The piezoelectric effect of LNK materials,the good biocompatibility of HA and porosity have been fully composited.Novel LNK and LNK-HA ceramics were fabricated by die pressing method.Porous LNK and LNK-HA ceramics were prepared by foaming method.The effects of preparing processing on the piezoelectric properties and dielectric properties of the materials were studied.The main conclusions are as follows:?1?Sintering temperature had significant effects on the performance of LNK ceramics.With the increase of sintering temperature,the growth of LNK crystals was gradually promoted,pores were removed,the density of LNK ceramics was increased and the piezoelectric and dielectric properties of LNK ceramics were improved.When sintered at 1000?,LNK ceramics exhibited the optimum piezoelectric properties: d₃₃=124.0p C/N,kp= 30.63%.?2?The properties of LNK-HA composite ceramics prepared by different mass fraction of LNK and HA were quite different.With the increase of the mass fraction of HA,the number of pores of LNK-HA ceramics was increased,the density was decreased and the dielectric and piezoelectric properties was decreased significantly.In addition,when sintered at appropriate temperatures,the internal pores of LNK-HA ceramics were gradually removed,the density was increased,the grains were grew and the better piezoelectric properties and dielectric properties were showed.When LNK and HA were compounded with mass ratio 9:1 and sintered at 1050?,LNK-HA ceramics exhibited the optimum properties: d₃₃=34.0 p C/N,?_r=648.12,tan?=0.0187.?3?In the processing of porous ceramics fabricated by egg white foaming method,the solid content of slurry and the addition of foaming agent had a significant effect on the performance of porous piezoelectric ceramics.With the increase of solid content,the viscosity of the slurry was increased,the foaming process was limited,the pore size of porous ceramics was reduced,the porosity was decreased,the density was increased and the piezoelectric and dielectric properties were showed an upward trend.With the addition of foaming agent,the porosity of porous ceramics was increased,the density was decreased,the pore size was decreased,the distribution of pore size was gradually uniform and the dielectric constant was greatly reduced.When solid content was 65% and foaming agent addition was 30%,porous LNK ceramics exhibited the best properties: d₃₃=48p C/N,?r=67.29.When solid content was 65% and foaming agent addition was 25%,porous LNK-HA ceramics exhibited the optimum properties: d₃₃=16.3p C/N,?r=52.91.