Sodium niobate, potassium hafnium zirconium titanate and calcium titanate are lead-free piezoelectric ceramics, which involve a new type of multielement lead-free piezoelectric ceramic composition and belong to the field of perovskite structure piezoelectric ceramics. The composition provided by the invention can be expressed by general formula (1-w)(k1-xnax) nbo3-wca (ti1-y-zzryhfz)O3, in which 0 < x < 1, 0 < y < 1, 0 < z < 1, 0 < w < 0.10. The lead-free piezoelectric ceramic composition may also contain one or more oxides, the general formula of which is (1-w)(k1-xnax) nbo3-wca (ti1-y-zzryhfz)O3+aM O (mol %), M O is one or more doped oxides, the molar ratio of a to the main component (1-w)(k1-xnax) nbo3-wca (ti1-y-zzryhfz)O3 is 0-3%, M is + 1-6 valence and can form solid oxides with oxygen. The optimal value of the piezoelectric constant d33 of the system's piezoelectric ceramic composition can reach more than 190pC/N, and the electromechanical coupling coefficients KP and kt can reach more than 45%. The process is stable, and it is made from traditional piezoelectric ceramic preparation technology and industrial raw materials, which is practical. Since the mid - 1940 - s found that barium titanate piezoelectric ceramic, piezoelectric properties especially the excellent and high Curie temperature of lead zirconate titanate Pb (Ti, Zr) 03 ceramics after the success of the development, structure characteristic is AB03 type of lead-based perovskite pressure electric ceramics research and development is very active, piezoelectric ceramics and piezoelectric ceramic device has been widely used in industry especially information industry field. Lead-based binary system represented by (Pb(Ti, Zr)03) and lead-based ternary piezoelectric ceramic material represented by (Pb(Ti, Zr)03) with the addition of a third group of elements [such as Pb(Pb(mg1/3nb2/3)03)] have excellent piezoelectric ferroelectric properties and high Curie temperature. Most of the piezoelectric ceramics used in industrial production are pb-based perovskite piezoelectric ceramics. Bismuth-layered lead-free piezoelectric ceramics have high Curie temperature, high anisotropy, but low piezoelectric activity. BaTi03 base piezoelectric ceramic Curie temperature is 120 ° C, only the piezoelectric properties of medium; Bia5Na (l. 5 ti03 lead-free piezoelectric ceramic piezoelectric stronger and easy modification can improve the piezoelectric, but around 210 ° C, the second phase change causes depolarization temperature below 210 ° C, modified to improve the performance of piezoelectric often accompanied by serious of depolarization temperature drops at the same time; Alkali niobate lead-free piezoelectric ceramics are difficult to have dense ceramic through traditional ceramic preparation technology, but its Curie temperature as high as 420 ° C for lead-free piezoelectric ceramics research hot spot.
Tag: Ti , Zr
