Lead-free piezoelectric materials with enhanced fatigue resistance
View Patent ↗A lead-free piezoelectric ceramic material has the general chemical formula xBi(A 0.5 Ti 0.5 )O 3 -y(Bi 0.5 K 0.5 )TiO 3 -z(Bi 0.5 Na 0.5 )TiO 3 , wherein x+y+z=1, x≠0, and A=Ni or Mg.
1. A lead-free piezoelectric ceramic material having the general chemical formula:
x Bi(A 0.5 Ti 0.5 )O 3 - z (Bi 0.5 Na 0.5 )TiO 3 , wherein x+z=1;
and wherein A=Mg or Ni.
2. The ceramic material of claim 1 , wherein said material comprises a solid solution having a stable perovskite structure at standard atmospheric conditions.
3. The lead-free piezoelectric ceramic material of claim 2 , wherein 0.01≦x≦0.70.
4. The lead-free piezoelectric ceramic material of claim 1 , having the general chemical formula wherein 0<x≦0.50.
5. The lead-free piezoelectric ceramic material of claim 1 , wherein said ceramic material has a piezoelectric strain coefficient d 33 equal to or exceeding that of a lead zirconate titanate perovskite.
6. The lead-free piezoelectric ceramic material of claim 1 , wherein said ceramic material has a maximum piezoelectric d 33 value in the range of about 200 pm/V to about 700 pm/V.
7. The lead-free piezoelectric ceramic material of claim 6 , wherein said ceramic material has a maximum piezoelectric d 33 value in the range of about 300 pm/V to about 400 pm/V.
8. The lead-free piezoelectric ceramic material of claim 1 , wherein said ceramic material has a maximum electromechanical strain value in the range of about 0.20 percent to about 0.35 percent.
9. The lead-free piezoelectric ceramic material of claim 1 , wherein said ceramic material has fatigue resistance equal to or exceeding that of a lead zirconate titanate perovskite.
10. The lead-free piezoelectric ceramic material of claim 1 having a Curie temperature (T c ) in the range of about 100° C. to about 500° C.
11. The lead-free piezoelectric ceramic material of claim 10 wherein the T c is in the range of about 300° C. to about 400° C.