PbTe 系合金是中溫區 (400~700 K) 熱電發電中最常用的熱電材料，其 ZT 值的研究主要集中在兩個方向：一、調控熱電塊材的載子濃度，進而增加塊材的電傳導率，以提升功率因子 (power factor) ；二、藉由摻雜使其散射聲子，降低熱傳導率而獲得較佳之熱電優值。
本研究以行星球磨法將鈉摻雜於 PbTe 粉體形成複合粉體，再以熱壓燒結於 450 ~ 550 ℃ 、 50 MPa 壓力下製成 PbTe : Na 複合塊材，檢討鈉摻雜量及熱壓燒結溫度對塊材的顯微結構及熱電性質的影響。
於製程上，有別於前人耗時耗能之熔煉法，本研究使用省時節能之行星球磨法，將鈉摻雜於PbTe粉體，再以熱壓燒結成為PbTe:Na熱電塊材。鈉摻雜量是由添加適量的Na2Te而得。利用行星球磨法所得之複合粉體之大小為1 ~ 5 μm，經熱壓燒結後會形成相對密度大於95%，晶粒大小為3 ~ 10 μm之緻密熱電塊材。摻雜的鈉粒子經熱壓燒結後並不存在於 PbTe 晶界上，而是於 PbTe 中產生間隙型固溶。
在熱電性質方面，PbTe : Na 塊材的電傳行為是隨鈉摻雜量而異，經鈉摻雜後會由p型半導體轉變成 n 型摻雜半導體的電傳行為。此外，功率因子 (S2σ) 則隨鈉添加量與量測溫度之增加而增加，其熱傳導率於整個量測溫度區間皆低於未摻雜之PbTe塊材，而鈉摻雜量 1.0 at.% 之 PbTe : Na 複合粉體以熱壓燒結於 500 ℃ 燒結所得之塊材，其熱電優值 (ZT) 於 700 K 時有最大值 0.81。
n 型傳導的 PbTe : Na塊材其室溫載子濃度、相對密度與導電率是隨熱壓燒結溫度之增加而增加；而Seebeck 係數是隨燒結溫度之增加而減少，其中鈉摻雜量為1.5 at.% 的PbTe：Na-550 ℃ 塊材，其功率因子在 650 K 時有最大值 1.33 mW/m-K2，此值為未摻雜鈉的 PbTe-550 ℃ 塊材之功率因子 (0.105 mW/m-K2) 的 28.4 倍。

To improve thermoelectric properties of PbTe:Na bulk materials, a manufacturing process that combined with planetary ball milling and hot-pressed sintering in the preparation of PbTe:Na bulk materials was studied. Samples with over 95% relative densities and 3~10 μm of grain sizes were obtained through hot-pressed at 500 ℃. Samples were measured and compared with those of raw ingots at temperatures from 300 K to 700 K to demonstrate the influence of Na contents on thermoelectric properties. The results revealed that increasing the Na contents improved the thermoelectric performance. PbTe: Na bulk showed the n-type conductivity. It was different from previous studies. A maximum ZT of 0.81 at 700 K was achieved for the n-type PbTe:1 at.% Na bulk.

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