Functionally graded MWCNT-HA composites were fabricated via hetero-aggregation and spark plasma sintering (SPS) process. The functionally-graded MWCNT–HA composites were further pressurelessly sintered at 1373 K in air condition to decompose the MWCNTs in the HA matrix. Consequently, structurally graded porous hydroxyapatite (HA) was successfully fabricated by introducing, followed by decomposing, of gradiently-included multi–walled carbon nanotubes (MWCNTs) at volume of 0–5 vol.%. Microstructure and Raman spectra of the sample clearly showed that no MWCNTs were present in the HA matrix. Moreover, pore and grain size of the structurally graded porous HA decreased with increasing MWCNT contents. It is expected that percolated MWCNTs make a degassing path for CO₂ gas generated by MWCNT decomposition, and also prohibit grain growth of HA. The results indicate that these advanced, layered, structure-controlled functionally graded MWCNT–HA composites and structurally graded porous HA are promising for a variety of new and challenging structural and biomaterial applications.

通过异质聚集和火花等离子体烧结（SPS）工艺制造功能分级的MWCNT-HA复合材料。将功能分级的MWCNT-HA复合材料在1373 K的空气条件下进一步进行无压烧结，以分解HA基体中的MWCNT。因此，通过引入，然后分解体积分数为0-5％的梯度包含的多壁碳纳米管（MWCNT），成功地构造了结构渐变的多孔羟基磷灰石（HA）。样品的显微结构和拉曼光谱清楚地表明，HA基质中不存在MWCNT。而且，随着MWCNT含量的增加，结构梯度多孔HA的孔和晶粒尺寸减小。预计渗透的MWCNT将成为CO ₂的脱气途径MWCNT分解产生的气体，也阻止了HA的晶粒长大。结果表明，这些先进的，分层的，结构受控的功能分级MWCNT-HA复合材料和结构分级的多孔HA具有广阔的前景，可用于各种新的具有挑战性的结构和生物材料应用。