| It is important to introduce the piezoelectric effect of BaTiO3 to HA-based bone graft material which can give bone implant material biological electrical activity like the natural bone However,its non-degradable piezoelectric phase content should reach 90%which far higher than the content of the cortical bone of the piezoelectric when the bone implant material having a match piezoelectric effect in bioelectrical activity with the natural phrenology.On the other hand,the compreesive strength of the composite can only reach the requirements of cancellous bone which can not meet the load requirements.At the same time,it is the presence of non-degradable material will make the potential risks.In order to solve this problem,this topic optimized BaTiO3/HA poling process,and makes the bone implant material having a piezoelectric effect of non-degradable piezoelectric phase content decreased.Compressive strength and piezoelectric constant d33 of biological piezoelectric composite ceramics under different BaTiO3 content doped by rare earth has been studied.Research achievements are as follows:(1)Poling process of BaTiO3 is optimized.The results showed that polarizing temperature higher,the more easily the electrical domain alignment arrangement,and the effect of polarization is better,but affected by resistivity with the polarizing temperature increase.With the increase of the polarization field strength,piezoelectric constant d33 increases,and the maximum value of the polarization field strength also resistant to breakdown voltage of BaTiO3.With the extension of time of polarization,the piezoelectric constant d33 was slight upward trend within the scope of the study.That is to say,the piezoelectric coefficient d33 of BaTiO3 can reach 76.2pC/N when be polarized in 55 ℃ 1.5kV/mm for 30min;(2)The phase of BaTiO3 powder doped by 1nol%Nd3+ tends to single with the reduction of pH,but the drying time of gel increases.And it is easy to obtain a single phase of BaTiO3 powder when Ba:Ti ratio greater than or equal to 1.As the annealing temperature rise,the content of BaCO3 in the power decrease,BaTiO3 powder tends to single.A single phase of BaTiO3 powders which doped by lmol%Nd3+ can be obtained in pH=4,Ba:Ti ratio is 1,and annealed at 750 ℃;(3)The piezoelectric coefficient d33 of Barium titanate ceramic doped by two different types and different content of rare earth has been studied,and it relates to radius and location of rare earth.The compressive strength of biological piezoelectric ceramics doped by 5mol%Er3+is 39.7%higher than that of the composite ceramics used by commercial barium titanate when the content of BaTiO3/HA composite biological piezoelectric ceramic piezoelectric phase is 90%. |
