本文選題：硅酸鎂(Mg_2SiO_4)陶瓷 + 燒結(jié)性能��； 參考：《陜西師范大學(xué)》2015年碩士論文

【摘要】：微波介電陶瓷目前是電介質(zhì)材料研究中的一類熱門材料,具有不同介電常數(shù)(εr)的微波介電材料在不同領(lǐng)域中各有所長,根據(jù)介電常數(shù)的不同,可以把微波介電陶瓷分為多種類型,其中低εr值的微波介電陶瓷材料是低溫共燒陶瓷(LTCC)技術(shù)中的一類重點(diǎn)研究對(duì)象,但此類材料大都有較高的燒結(jié)溫度,針對(duì)其中有優(yōu)良微波介電性能的微波介質(zhì)陶瓷,許多研究者投入大量的精力來改善它們的燒結(jié)性能和微波介電性能,以實(shí)現(xiàn)此類材料在通信領(lǐng)域的廣泛應(yīng)用,進(jìn)而滿足現(xiàn)代通信技術(shù)在各個(gè)領(lǐng)域的發(fā)展需求。硅酸鎂(Mg2SiO4)陶瓷作為一種典型的低ε,微波介電陶瓷同樣具有燒結(jié)溫度高、難致密的特點(diǎn),其本身良好的微波介電性能難以發(fā)揮,從而限制了其在LTCC等技術(shù)領(lǐng)域的使用。本文以Mg2SiO4陶瓷為研究對(duì)象,針對(duì)其燒結(jié)溫度高,易生成第二相等問題,在參考已有文獻(xiàn)的基礎(chǔ)上制定實(shí)驗(yàn)方案,利用X射線衍射、掃描電子顯微鏡(SEM)以及微波網(wǎng)絡(luò)分析儀等技術(shù)手段來研究不同工藝對(duì)Mg2SiO4微觀結(jié)構(gòu)、燒結(jié)性能和微波介電性能的影響,主要內(nèi)容包括：(1)利用化學(xué)法合成Mg2SiO4粉體并制備其陶瓷,通過控制反應(yīng)條件實(shí)現(xiàn)原料分子間的充分接觸,在較低預(yù)燒溫度(890℃)獲得了以Mg2SiO4為主相的預(yù)燒粉體,通過不同的測(cè)試手段研究Mg2SiO4陶瓷的物相組成、顯微結(jié)構(gòu)和微波介電性能,XRD圖譜分析結(jié)果顯示：實(shí)驗(yàn)過程中一直伴有MgO存在,陶瓷樣品的燒結(jié)溫度區(qū)間在1350℃-1500℃,1475℃燒結(jié)的陶瓷表現(xiàn)出良好的微波介電性能：εr=6.34, Q×f=128000GHz,τf=-46ppm/℃。(2)采用傳統(tǒng)固相法制備Mg2SiO4陶瓷,通過調(diào)控Mg/Si非化學(xué)計(jì)量比(Mg/Si=2.2.025.2.04.2.05)合成Mg2SiO4,使MgO適量增多,當(dāng)Mg/Si=2.05時(shí)得到較純物相的Mg2SiO4粉體,通過分析不同組分制備的Mg2SiO4陶瓷的性能,探究了物相組成對(duì)Mg2SiO4陶瓷微波介電性能的影響。結(jié)果表明：Mg/Si=2.05組分配比的陶瓷粉體在1350℃燒結(jié)的Mg2Si04陶瓷具有較好的微波介電性能：εr=5.67,Q×f=64800GHz,τf=-40ppm/℃。(3)在采用MgO:SiO2=2.05:1非化學(xué)計(jì)量比制備物相較純Mg2SiO4粉體的基礎(chǔ)上,添加氟化鋰(LiF)來改善Mg2SiO4陶瓷的燒結(jié)性能,實(shí)驗(yàn)研究了LiF對(duì)該陶瓷燒結(jié)溫度、微觀形貌及微波介電性能的影響,實(shí)驗(yàn)結(jié)果顯示,添加一定量的LiF可以使Mg2SiO4陶瓷的最佳燒結(jié)溫度從1350℃降到950℃左右,并且陶瓷的介電常數(shù)εr和品質(zhì)因數(shù)Q×f與LiF的添加量和燒結(jié)溫度有關(guān)。添加4wt%LiF,在940℃燒結(jié)5h的陶瓷樣品表現(xiàn)出良好的微波介電性能：εr=6.58,Q×f=132900GHz, τf=-57ppm/℃,且Mg2SiO4+4wt%LiF的陶瓷胚體可以與銀粉在950-C的條件下實(shí)現(xiàn)共燒。(4)Mg2SiO4陶瓷具有負(fù)的諧振頻率溫度系數(shù)(tf值),在添加4wt%LiF降溫的基礎(chǔ)上,同時(shí)添加24wt%TiO2來調(diào)節(jié)陶瓷的tf值。通過XRD圖分析發(fā)現(xiàn)在燒結(jié)過程中LiF、TiO2和Mg2SiO4之間發(fā)生了化學(xué)反應(yīng),具有較多的物相存在,微波介電性能測(cè)試和分析表明：添加24wt%TiO2可以將Mg2SiO4陶瓷的tf值調(diào)節(jié)近零,LiF作為燒結(jié)助劑可以降低陶瓷的燒結(jié)溫度,使樣品在950℃-970℃的燒結(jié)溫區(qū)得到性能穩(wěn)定的陶瓷,950℃燒結(jié)制備的陶瓷具有最佳微波介電性能：8,=7.44,Q×f=38400GHz,τf=0.37ppm/℃。近零的tf值可以使該陶瓷有更加廣泛的應(yīng)用價(jià)值。
[Abstract]:Microwave dielectric ceramics are currently one of the most popular materials in the research of dielectric materials. Microwave dielectric materials with different dielectric constant (R) have their own advantages in different fields. Microwave dielectric ceramics can be divided into various types according to the dielectric constant, and microwave dielectric ceramics with low R value are low temperature co fired ceramics (LTCC). However, most of these materials have high sintering temperature. In view of the microwave dielectric ceramics with excellent microwave dielectric properties, many researchers have invested a lot of energy to improve their sintering and microwave dielectric properties, so as to realize the wide application of such materials in the field of communication and to meet the present situation. Magnesium silicate (Mg2SiO4) ceramics, as a typical low epsilon, has the characteristics of high sintering temperature and difficult density, and its good microwave dielectric properties are difficult to play. Thus, the use of Mg2SiO4 ceramics in the field of LTCC technology is limited. This paper takes Mg2SiO4 ceramics as the research object. In view of its high sintering temperature and easy generation of second equal problems, the experimental scheme was formulated on the basis of reference literature. X ray diffraction, scanning electron microscope (SEM) and microwave network analyzer were used to study the effects of different processes on the microstructure, sintering properties and microwave dielectric properties of Mg2SiO4. The main contents included the main contents. (1) the Mg2SiO4 powders were synthesized by chemical method and their ceramics were prepared. By controlling the reaction conditions, the full contact between the raw materials was realized. The prefired powders with Mg2SiO4 as the main phase were obtained at the lower prefiring temperature (890 degrees C). The phase composition, microstructure and microwave dielectric properties of Mg2SiO4 ceramics, and the XRD atlas were studied by different testing methods. The results show that MgO has been accompanied by the presence of MgO, the sintering temperature range of ceramic samples at 1350 C -1500 C and 1475 C sintered ceramics showed good microwave dielectric properties: epsilon r=6.34, Q x f=128000GHz, tau f=-46ppm/ C. (2) the traditional solid-phase method was used to prepare Mg2SiO4 ceramics by controlling the non stoichiometric ratio of Mg/Si (Mg/Si=2.). 2.025.2.04.2.05) synthesis of Mg2SiO4, increase the amount of MgO, and get Mg2SiO4 powder of pure phase when Mg/Si=2.05. By analyzing the properties of Mg2SiO4 ceramics prepared by different components, the influence of phase composition on the microwave dielectric properties of Mg2SiO4 ceramics is explored. The results show that the ceramic powders of Mg/Si= 2.05 groups are sintered at 1350 degrees centigrade at Mg2Si04. The ceramics have good microwave dielectric properties: epsilon r=5.67, Q x f=64800GHz, tau f=-40ppm/ C. (3) on the basis of MgO:SiO2=2.05:1 non stoichiometry compared with pure Mg2SiO4 powder, lithium fluoride (LiF) is added to improve the sintering properties of Mg2SiO4 ceramics. The sintering temperature, micromorphology and microwave dielectric properties of LiF on the ceramics are studied experimentally. The experimental results show that the optimum sintering temperature of Mg2SiO4 ceramics can be reduced from 1350 to 950 C by adding a certain amount of LiF, and the dielectric constant epsilon R and the quality factor Q x f are related to the addition of LiF and the sintering temperature. The ceramic samples sintered at 940 C at 940 C show good microwave dielectric properties. : epsilon r=6.58, Q x f=132900GHz, tau f=-57ppm/ C, and Mg2SiO4+4wt%LiF ceramic embryo can be co fired with silver powder under the condition of 950-C. (4) Mg2SiO4 ceramics have a negative resonant frequency temperature coefficient (TF value). On the basis of adding 4wt%LiF cooling, the 24wt% TiO2 is added to regulate the ceramic TF value. During the process, the chemical reaction between LiF, TiO2 and Mg2SiO4 has a lot of phase. The microwave dielectric properties test and analysis show that the addition of 24wt%TiO2 can adjust the TF value of Mg2SiO4 ceramics to nearly zero. The sintering temperature of the ceramics can be reduced by LiF as the sintering agent, and the sample can be stable in the sintering temperature zone of 950 C -970. Ceramics prepared by sintering at 950 C have the best microwave dielectric properties: 8, =7.44, Q x f=38400GHz, tau f=0.37ppm/ C. The near zero TF value can make the ceramics more widely applied.
【學(xué)位授予單位】：陜西師范大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：TQ174.1

【參考文獻(xiàn)】

相關(guān)期刊論文 前1條

1 婁本濁;;Ti-B位置換改性Mg_2SiO_4陶瓷微結(jié)構(gòu)與微波介電性能研究[J];江蘇陶瓷;2008年05期

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本文編號(hào)：1992303