磁头/磁盘滑动接触下磁盘温度及热退磁临界条件的研究

采用二维轴对称有限元模型计算磁头/磁盘滑动接触下,铝质磁盘的稳态温度和热应力场以及热退磁临界条件.结果表明:磁盘温度在极短时间内升至摩擦稳态值,然后缓慢线性升高到最终稳态值;经过充分热传导和热交换后磁盘的温度梯度较小,此时磁层内的热应力集中分布于磁盘固定端边缘附近;磁盘的稳态温度和热应力均随速度增大而增大,且载荷越大其值增大越快;热应力小于1.2 GPa时所对应的速度和载荷为安全工况;温升大于373 K时所对应的工况将导致磁盘退磁.

Temperature of Hard Disk and Critical Condition for Heat-Induced Demagnetization in Head/Disk Continuous Sliding Contact

Finite element analysis of head/disk continuous sliding contact was performed to investigate temperature field and thermal stress field due to frictional heat using an axisymmetric thermal model. Characteristic temperature rise with sufficient sliding time was exhibited. Additionally, effects of sliding velocity and contact pressure as well as frictional coefficient on the maximum temperature rise and maximum thermal stress were examined. From the simulation results and the demagnetization temperature available, the critical condition for heat-induced demagnetization in magnetic recording disks was deduced. It is shown that, the temperature of the disk increases rapidly to frictional steady-state value and then slowly to the maximum value at the enclosed air. The temperature gradient of the disk falls after longtime heat conductivity and exchange in head/disk continuous sliding contact. Higher velocity or/and heavier load produce significantly higher temperature rise and thermal stress of the disk. Velocity and load resulting in the maximum thermal stress smaller than 1.2 GPa is the safe operating condition for the magnetic disk, at the same condition with temperature higher than 373 K it will lead heat-induced demagnetization.