在壓電材料中，含鉛固溶體由于制備工藝簡單，成本低，又具有較好的力學性能和穩定的壓電性能，在壓電元件領域一直占主導地位。但這類壓電陶瓷材料的主要成分PbO (或Pb3O4)的含量約占原料總量的70％，其在生產、使用和廢棄的過程中都會給人類和自然環境造成嚴重的傷害。因而，在壓電陶瓷領域，無鉛壓電陶瓷從環保的角度考慮越來越引起人們的重視。而目前開發的無鉛壓電陶瓷體系仍存在很多方面的問題，有待進一步的研究和探索。
在當前研究的無鉛壓電陶瓷體系中，鈣鈦礦結構型陶瓷具有較高的機電耦合系數，被認為是一種有著廣泛應用前景的壓電材料。在鈣鈦礦型無鉛壓電陶瓷中，目前研究得比較多的體系有BaTiO3基、鈦酸鉍鈉（NBT）基和鈮酸鉀鈉（KNN）基。BaTiO3基材料壓電性能中等，且難以通過摻雜來大幅度地改變性能；而Na0.5Bi0.5TiO3（NBT）具有較高的壓電性能，但去極化相變溫度較低；K0.5Bi0.5TiO3（KBT）和KxNa1-xNbO3（KNN）具有較高的去極化溫度，但該組分在未摻雜時用傳統方法很難燒結致密，且還有易吸潮的缺點。
本實驗中采用普通固相燒結法，制備了致密化的摻雜不同稀土元素的KNN基和KBT基陶瓷以及（1－x）BaTiO3-x( K0.5Bi0.5)TiO3（BK100x）復合陶瓷。希望通過對KNN、KBT和BK陶瓷的制備和性能表征，獲得具有較好壓電性能的無鉛壓電陶瓷材料。本文工作主要分為以下幾個部分：
采用X射線衍射（X-ray diffraction,XRD）分析技術對所制得的壓電陶瓷進行相結構分析，以確定所制得樣品是否具有鈣鈦礦結構；通過比較利用原子力顯微鏡(atomic force microscope,AFM）表征的在不同燒結條件下得到的陶瓷樣片的表面形貌，分析了燒結溫度與燒結樣片表面晶粒大小的關系；嚴格控制了制備過程中的各個環節，著重分析了KNN和KBT陶瓷的燒結工藝和極化條件中的主要影響因素及影響特征，確定出了較佳的制備工藝參數；研究了BK的介電常數溫度譜，測試了在不同頻率下該陶瓷的介電性能在升溫過程中的變化，并著重分析了1KHz下介電性能和溫度的變化關系；較為細致的測定了BK陶瓷的壓電性能，比較了在不同燒結溫度下所得到的樣品的壓電性能參數。最終獲得了致密度較高，具有良好壓電性能的無鉛陶瓷BK10。其主要壓電性能為：d 33=71pC/N，kp=0.18，tanδ=2.17%，Qm=189。
關鍵詞：無鉛，壓電陶瓷， KNN，KBT，BK，制備工藝，介電性能，壓電性能
THE PREPARATION AND PROPERTIES OF PEROVSKITE-TYPE LEAD-FREE PIEZOCERAMICS
ABSTRACT
Among sorts of piezoelectric material systems, lead-based PZT material has been dominating the market for piezoceramics component due to their excellent piezoelectric properties. Since PZT contains more than 70 %( wt.) lead which is toxic, it is apprehensive that PZT has harmful influence upon environment and our human beings. Through the heightening of the public’s awareness towards global environment protection and sustainable development of the world society, it’s necessary and urgent to replace PZT by those harmless lead-free piezoceramics while maintaining comparable piezoelectric properties and reasonable phase transition temperature.
In lead-free piezoceramics fields, Potassium sodium Niobate (KNN) and bismuth potassium titanate (KBT) reveal improved piezoelectric properties and correspondingly high depolarization temperature. However, their hygroscopicity and sinterability make it difficult to obtain well-densified KNN-based or KBT-based ceramics. The goal of our study is to optimize the sintering and piezoelectric character of KNN and KBT ceramics,especially to obtain ceramics possessing good properties.
The main works are as follows: KNN-based, KBT-based ceramics doped with rare elements and BK ([(1-x) BaTiO3-x (K0.5Bi0.5) TiO3] ceramics were synthesized via traditional solid state reaction, sintered under atmospheric pressure with different additive as sintering aid. In this study, the phase structures of all samples were detected through XRD (X-Ray Diffraction), the microstructures of the samples’ surface were analyzed by AFM (Atomic Force Microscope). And at last, their dielectric and piezoelectric properties were investigated. The KNN-based and KBT-based ceramics in this study performed midding dielectric properties, meanwhile the other compositions BK10(90%BaTiO3-10%(K0.5Bi0.5)TiO3) gave optimized piezoelectric properties(d33=71pC/N，kp=0.18，tanδ=2.17%，Qm=189).
