A novel adaptive shearing-gradient thickening polishing (AS-GTP) method is first proposed to improve surface accuracy and restrain subsurface damage on lithium niobite (LiNbO₃ or LN) crystal. The material removal rate (MRR) in AS-GTP is established according to adaptive real-shearing flow, temperature-induced gradient thickening (GT) mechanism, and plastic indentation on active GT abrasive concept. The MRR prediction model is verified by the AS-GTP experiments. Results from the theoretical calculation based on the MRR prediction model are closed to that from experimental data, and the maximal difference between the experiment results and theoretical calculation is no greater than 9.5%. The microstructure of the thermosensitive particle (NIPAM-ODA, the copolymer of N-isopropylacrylamide and octadecyl acrylate) has amphiphilic property and results in the gradient thickening for AS-GTPS. Under the conditions of temperature of T 38 °C, average abrasive size of D_a 0.6 μm, rotational speed of v_r 600 min⁻¹, abrasive concentration of W 12 vol % and gradient-thickening threshold (shear rate 300 s⁻¹), surface damage depth (D_d) and surface roughness (Ra) also decline to a minimum critical threshold (<1 nm). The results indicate that the AS-GTP is a promising processing method to achieve subsurface damage inhibition and ultra-smooth surface for LN crystal high-efficiency machining.

首先提出了一种新的自适应剪切梯度增厚抛光（AS-GTP）方法，以提高表面精度并抑制亚铌酸锂（LiNbO ₃或LN）晶体。AS-GTP中的材料去除率（MRR）是根据自适应真实剪切流，温度引起的梯度增厚（GT）机理以及基于主动GT磨料概念的塑性压痕确定的。通过AS-GTP实验验证了MRR预测模型。基于MRR预测模型的理论计算结果与实验数据接近，并且实验结果与理论计算之间的最大差值不大于9.5％。热敏颗粒（NIPAM-ODA，N-异丙基丙烯酰胺和丙烯酸十八烷基酯的共聚物）的微观结构具有两亲性质，导致AS-GTPS的梯度增稠。在T 38°C的温度条件下，D的平均磨料尺寸_a为0.6μm，转速为v _r 600 min ^-1，磨料浓度为W 12 vol％，梯度增厚阈值（剪切速率300 s ^-1），表面损伤深度（D _d）和表面粗糙度（Ra）也下降至最小临界阈值（<1 nm）。结果表明，AS-GTP是实现LN晶体高效加工的抑制亚表面损伤和超光滑表面的一种有前途的加工方法。