【摘要】：常用的負(fù)溫度系數(shù)(NTC)熱敏電阻是由具有尖晶石結(jié)構(gòu)的過渡族金屬氧化物固溶體組成的。NTC熱敏材料主要應(yīng)用于溫度測(cè)量、溫度控制和抑制浪涌電流等方面。作為一種電子材料,NTC熱敏材料的小型化和薄膜化是發(fā)展的必然趨勢(shì)。常用的薄膜制備工藝主要有絲網(wǎng)印刷法、脈沖激光法、蒸發(fā)法、磁控濺射法、溶膠凝膠法和水熱沉積法。其中,傳統(tǒng)的薄膜制備方法普遍存在工藝復(fù)雜、制備效率低和后期處理困難的不足,而水熱法制備薄膜是在液相中一次完成,無需退火或晶化處理,避免了薄膜在后期處理過程中可能導(dǎo)致的晶粒粗化、薄膜卷曲開裂以及薄膜與基體反應(yīng)而引起薄膜性能的不穩(wěn)定等問題。本研究采用水熱沉積法制備鎳錳系尖晶石結(jié)構(gòu)熱敏薄膜材料,并在薄膜中摻雜A1和Zn離子,采用XRD、SEM、XPS和阻溫測(cè)試等方法研究了材料的組織結(jié)構(gòu)和性能,實(shí)現(xiàn)了改善材料電學(xué)性能,獲得最優(yōu)材料配方的目的。本論文的主要研究?jī)?nèi)容如下:通過水熱沉積法制備尖晶石NTC熱敏薄膜材料。首先在氧化鋁陶瓷基片上水熱沉積制備NiMn1.8A10.2O4熱敏薄膜。研究不同反應(yīng)時(shí)間(2 h、5 h、10 h和15 h)對(duì)薄膜的微觀結(jié)構(gòu)和電學(xué)性能的影響。結(jié)果表明,反應(yīng)溫度為230℃,反應(yīng)時(shí)間2 h條件下即可沉積出致密性良好的熱敏薄膜。薄膜晶粒尺寸隨著反應(yīng)時(shí)間的增加逐漸增大,反應(yīng)在2h時(shí),晶粒平均直徑在2.5μm,隨著反應(yīng)時(shí)間增加到15 h,平均晶粒尺寸達(dá)到了 5.4μm。不同反應(yīng)時(shí)間沉積的薄膜均具有良好的NTC特性,隨反應(yīng)時(shí)間增加,材料常數(shù)和激活能隨反應(yīng)時(shí)間的增大而增大。在反應(yīng)時(shí)間為15 h時(shí),其材料常數(shù)達(dá)到了 4645 k。本研究表明水熱法是一種低溫下制備良好NTC熱敏特性薄膜材料的新方法,為用水熱法制備NTC熱敏薄膜提供技術(shù)支撐。通過水熱沉積法制備NiMn1.8-xA10.2ZnxO4(0 ≤ x ≤ 0.2)系NTC熱敏薄膜材料。首先在優(yōu)化的水熱沉積工藝參數(shù)(230℃,15 h)下制備摻雜Zn的鎳錳鋁尖晶石結(jié)構(gòu)NTC熱敏薄膜,主要研究Zn含量對(duì)薄膜的微觀結(jié)構(gòu)和電學(xué)性能的影響。通過SEM可以觀察到摻雜Zn的薄膜的典型微觀結(jié)構(gòu),下層是與基底緊密結(jié)合的納米片狀結(jié)構(gòu),上層是顆粒狀結(jié)構(gòu)。隨著Zn含量的增加,顆粒尺寸明顯增大。通過XPS分析發(fā)現(xiàn):隨著Zn含量的增加,Mn總含量的減少,膜中Mn2+的含量減少,而Mn+3/Mn+4含量增加。通過電學(xué)性能分析,表明所沉積的薄膜具有良好的負(fù)溫度系數(shù)(NTC)熱敏特性,其室溫電阻隨著Zn含量的增加而增大,材料常數(shù)在4000～4200 K之間。摻雜Zn的薄膜在150℃老化300 h后,即可得到穩(wěn)定的NTC熱敏薄膜,最大老化率為22.2%,老化研究表明通過摻雜Zn能得到穩(wěn)定性較高的NTC熱敏薄膜材料。
[Abstract]:The commonly used negative temperature coefficient (NTC) thermistor is composed of transition metal oxide solid solution with spinel structure. NTC thermistor is mainly used in temperature measurement, temperature control and suppression of surge current. As an electronic material, the miniaturization and thinning of NTC thermal sensitive materials is an inevitable trend. The main techniques of thin film preparation are screen printing, pulsed laser, evaporation, magnetron sputtering, sol-gel and hydrothermal deposition. Among them, the traditional preparation methods of thin films have many disadvantages, such as complex process, low preparation efficiency and difficulty in post-treatment. However, hydrothermal preparation of thin films is completed in the liquid phase, without the need of annealing or crystallization. The problems of coarsening, crimp cracking and the instability of the film properties caused by the reaction between the film and the substrate are avoided. In this paper, Ni-Mn spinel structure thermistor thin films were prepared by hydrothermal deposition. The microstructure and properties of the films were studied by doping Al and Zn ions, XRD,SEM,XPS and temperature resistance test. The purpose of improving the electrical properties of materials and obtaining the optimal material formula is achieved. The main contents of this thesis are as follows: spinel NTC thin films were prepared by hydrothermal deposition. Firstly, NiMn1.8A10.2O4 thin films were prepared by hydrothermal deposition on alumina substrates. The effects of different reaction time (2 h, 5 h, 10 h and 15 h) on the microstructure and electrical properties of the films were studied. The results show that the thermosensitive films with good densification can be deposited at 230 鈩，

本文編號(hào)：2326525