ニオブ-チタン合金およびバナジウム-ニオブ合金の複合窒化物を作成する目的で60ニオブ-40チタン(wt%)合金粉末(粒径約80μ)ニオブ0チタン合金板(Nb:20,40,60,80wt%)および50バナジウム-50ニオブ(wt%)合金板を窒素中(1atm),700～1350℃で窒化し,断面の組織観察,EPMA解析ならびにX線解析により反応状況を調べ,合金組成の均一な複合窒化物合成の可能性を検討した。ニオブ0チタン合金ではまず高チタン濃度の針状窒化物を生成した。高チタン濃度の窒化物の析出した周辺は高ニオブ濃度の低級窒化物または合金相となった。さらに反応が進むと高チタン相と高ニオブ相が窒化増量にともない反応して表面から合金組成の複合窒化物を生成した。60Nb-40Ti合金粉末は1300℃,4時間で,またNb-Ti合金板(Nb:20,40,60,80wt%,厚さ約0.3mm)は1350℃,48時間でそれぞれ合金組成の複合窒化物となった。50バナジウム-50ニオブ合金では針状窒化物は奪成せ劣表面から合金組成の窒化物が層状に成長した。50バナジウム-50ニオブ合金板(厚さ約0.8mm)は.1350℃,48時間で合金組成の複合窒化物となった。

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Electric conductance and density of molten oxides were measured in the systems, 2PbO⋅B₂O₃-CuO, 2PbO⋅B₂O₃-TiO₂ and 2PbO⋅B₂O₃-Fe₂O₃, containing CuO, TiO₂ and Fe₂O₃ from 0 to 25mol% respectively. The structure of these molten oxides and behaviours of Cu²⁺, Ti⁴⁺ and Fe³⁺ were discussed.
Conduction mechanism in these melts is ionic, the same as in the system PbO-B₂O₃, and the mobility of cations depends upon the structure of borate complex anions.
In 2PbO⋅B₂O₃-CuO melts, CuO is considered to dissociate into Cu²⁺ and O^2- ions. In the melts containing less than about 15mol% CuO, the degree of dissociation of borate complex anions seems to increase with increasing CuO content. The increase in the mobility of cations (mainly Pb²⁺) and the decrease in the partial molar volume of CuO are considered to be caused by the dissociation of CuO and borate complex anions. In the melts containing more than about 15mol% CuO, contribution of Cu²⁺ ion to electric conductance increases. The concentration of free O^2- ion also increases, as in the system PbO-B₂O₃ containing more than 75mol% PbO. Anionic contribution to electric conductance is no longer negligible, when the concentration of O^2- ion is high.
Ti⁴⁺ and Fe³⁺ are considered to form oxyacid ions. When TiO₂ or Fe₂O₃ content increases, borate complex anions associate into larger or more complex anions. Then, mobility (equivalent conductance) of Pb²⁺ ion decreases. The partial molar volume of TiO₂ or FeO_1.5 increases in the melts containing TiO₂ or Fe₂O₃ up to about 10mol%. But in the melts containing more than about 10mol% TiO₂ or Fe₂O₃, the increase of free Ti⁴⁺ or Fe³⁺ reduces the partial molar volume of TiO₂ or FeO_1.5.

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Nb₂O₅-V₂O₅-P₂O₅系ガラスを熱処理して導電率の高い結晶化ガラスを得る目的で本研究を行なった。この系のガラス化限界組成は2元系の限界組成0.9V₂O₅・0.1P₂O₅と0.6Nb₂O₅・0.4P₂O₅を結ぶ線の近傍にあった。ガラスは電子伝導性であり,その導電率はV₂O₅濃度が大であるほど大であり,同一V₂O₅濃度ではP₂O₅をNb₂O₅で置換すると増加した。示差熱分析で明瞭な結晶化の発熱ピークが観察されるガラスについて,結晶化の熱処理を行なった。(V₂O₅+Nb₂O₅)のモル分率が0.8のガラスC,Dは,0.7のガラスA,Bに比較して結晶化速度が大であった。Nb₂O₅は核形成の働きをし,これによって微細な結晶が均一に析出した。熱処理による結晶化にともなって,導電率(250℃)はガラスAでは10^-4から10mm2Ω^-1・cm^-1に,ガラスBでは10^-6から10^-3SZ^-1Ω^-1・cm^-1に,ガラスC,Dでは10^-3から10^-1Ω ^-1・cm^-1に変化し,約2ケタ以上増加した。析出結晶のうち電導に寄与するのはV₂O₅であり,これに5mol%Nb₂O₅を固溶した結晶の導電率は10-1Ω-1・cm-1であった。熱処理によってこの結晶が析出し,たがいに連結するようになると導電率は急速に増加した。結晶が微細であるほど連結する部分が多くなった。

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Hydrous lithium metatitanate (Li₂TiO₂⋅nH₂O) fine particles were formed from the alcoholic solution of lithium and titanium alkoxides. Titanium tetraisopropoxide was added to the butanol or ethanol solution of lithium tert-butoxide, and then the mixed solution was hydrolyzed with H₂0-i-C₂H₂OH solution. In the case of Ti/Li mole ratio=0.5, the sharp XRD profiles of Li₂TiO₃only were observed in the XRD pattern of the precipitate when heattreated at 800°Cfor 1 h. The weight loss of 15% of the precipitate was observed due to dehydration in the temperature range from 100°C to about 800°C, which corresponded to n=1.4 in the chemical formula described above. The remarkable grain growth of the precipita te by the heat-treatment at 800°C for 1 h was recognized in the SEM observation; the wellshaped Li₂TiO₃ particles of about 200 nm in length was obtained.

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Redox equilibria of glass melts with oxygen and CO₂-CO mixtures containing oxygen partial pressures from 10⁰ to 10^-14 atm were studied. The structure-sensitive properties of quenched glasses such as specific resistivity, were found to be correlated to the redox equilibrium.
In the glass melts of 5Fe₂O₃⋅95RP₂O₆ and 7TiO₂⋅93RP₂O₆, the concentration ratios [Fe²⁺]/[Fe³⁺] and [Ti³⁺]/[Ti⁴⁺] were the highest for the lowest basicity (R=Mg), decreasing in the order of Mg, Ca, Ba (O-type), while concentrations of high-valent ions (Fe³⁺, Ti⁴⁺) remained nearly unchanged and those of low-valent ions (Fe²⁺, Ti³⁺) decreased.
On the other hand, in the glass melts containing larger amounts of Fe₂O₃ such as 20Fe₂O₃⋅80RP₂O₆, the ratio [Fe²⁺]/[Fe³⁺] increased with increasing basicity (R-type). At high oxygen partial pressures, ferric ion concentration remained nearly unchanged and ferrous ion increased with increasing basicity. At low oxygen partial pressures ferrics ion decreased and ferrous ion concentration remained nearly unchanged.
The specific resistivities of the quenched glasses of 7TiO₂⋅93RP₂O₆ and 20Fe₂O₃⋅80RP₂O₆, which were obtained from the melts in redox equilibria, decreased with increasing basicity by replacing R with Mg, Ca, Ba. A minimum of specific resistivity was observed when the concentration ratio of low to high valent ions of transition metal was approximately equal to unity. However, this ratio decreased for the glasses of 7TiO₂⋅93RP₂O₆ and increased slightly for 20Fe₂O₃⋅80RP₂O₆ as the basicity increased. TiO₂ was more effective than Fe₂O₃ on the lowering of specific resistivity.
It is concluded from these experimental results that the redox equilibria in the melts of 5Fe₂O₃⋅95RP₂O₆ and 7TiO₂⋅93RP₂O₆ are expressed as,
2[XO_x]^(2x-n-m)-=2Xⁿ⁺+(2x-m)O^2-+m/2 O₂
where X is Fe or Ti and m=1. Complex oxiacid ions Fe₂O₅^4- or TiO₄^4- seemed to be involved in the equilibria.
In the melts of 20Fe₂O₃⋅80RP₂O₆, equilibrium is expressed as,
2[XO_x]^(2x-n-m)-+(m-2(x-y))O^2-=2[XO_y]^(2y-n)-+m/2 O₂
The oxygen ion coordination number of the ferrous complex ion has not been found in the present work.

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To elucidate the microstructure, sintering process and developement of second phase at the grain boundary, model grain boundary was prepared and observed, by contacting two polished surfaces of sintered spinel Cu_0.75Fe_2.25O_4+x and annealing. Because the sintered specimen was grown its grains extremely (above several hundreds microns diameter), little grain growth and little boundary migration occurred during annealing for bonding. Therefore, the bonded part could be cleaved again along the new grain boundary, and the both sides of boundary surface were observable.
The oxygen content of the specimen was controlled by previous annealing, and the bonding was carried out between 1100°C and 1180°C. The bonding was nearly complete at the conditions, in which specimen was oxidized and the bonding was little when it was reduced (Fig. 1, 4). It was confirmed that the new grain boundary was not different from the grain boundary of the inner part of sintered body (Fig. 2, 3).
The crystallographic orientation of the grains at the bonded boundary was determined by measuring the orientation of α-Fe₂O₃ crystallites, which developed in the spinel crystals by oxidation. Various step configurations were observed at the cleaved boundary surfaces (Fig. 5, 6). The relation between step configuration and crystallographic orientation of the grains at the boundary was plotted in the stereographic projection diagram (Fig. 7). It is confirmed that the (111) plane is one constituent of the step, and it seems to be stable at the grain boundary (Fig. 8).
The process of developing α-Fe₂O₃ or CuFeO₂ crystallites at the grain boundary of spinel was observed, when specimen was oxidized or reduced. It was confirmed from the observation of the cleaved boundary surfaces that the both crystallites developed along the (111) plane of spinel. The various configurations of developed crystallites were related to the orientation of the spinel crystal grains at the boundary (Fig. 9, 10).

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To elucidate redox equilibria of chromium ions in glass melts of the system Cr₂O₃-RP₂O₆(R; Mg, Ca, Ba, Ca_0.5K), effects of oxygen partial pressure, basicity of melts, and total chromium concentration on the equilibria were studied at 1200°C and 1300°C. Absorption spectra of Cr²⁺ and Cr³⁺ in glasses of these systems were measured, and the results were analyzed in terms of ligand field theory. Oxygen coordination of chromium ions and the nature of Cr-O bond in glass and melts were discussed.
The results are the followings:
(1) Both Cr²⁺ and Cr³⁺ in glass are in octahedral symmetry and the average coordination number is six, as the hydrated complex ions in aqueous solutions. Partial covalent nature is found in Cr³⁺-O bond in glass: Racah's parameter of inter electronic repulsion B of Cr³⁺ in glass is 750cm^-1 and is rather small in comparison with B of free Cr³⁺, 918cm^-1.
(2) Equilibrium concentration ratios of Cr²⁺/Cr³⁺ and Cr³⁺/Cr⁶⁺ in the melts decrease with increasing oxygen partial pressure and basicity of the melts. From these results, redox reactions of chromium ions were described by the following equations:
CrO_l^(2-2l)++1/4O₂+(h-l-1/2)O^2-=CrO_h^(3-2h)+………………………………………(1)
CrO_h^(3-2h)++3/4O₂+(5/2-h)O^2-=CrO₄^2-…………………………………………………(2)
where h and l are the parameters related to the partial covalent nature of chromium-oxygen bonds, not the coordination numbers of chromium oxi-acid complex ions.
(3) The Cr²⁺/Cr³⁺ ratio varies with increasing total chromium concentration through a minimum value, and it is considered that the values of h and l vary with total chromium concentration. In glasses, however, peak positions of Cr³⁺ absorption spectra and B parameter which shows the nature of Cr³⁺-O bond, did not change with Cr³⁺ concentration. The behaviours of chromium ions in melts were discussed in comparison with glasses.

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CuO-V₂O₅-P₂O₅系ガラスの電気伝導に関して研究を行った. この系のガラス化領域で最も多量に遷移金属酸化物を含有するガラスの組成は, 0.25-0.4CuO・0.7-0.55V₂O₅・0.05P₂O₅であった. 4V₂O₅・P₂O₅にCuOを0-40mol%添加した組成のガラスでは, V₂O₅の減少にもかかわらずCuOの増加とともに導電率は増加し, CuOはV₂O₅と同様, 伝導に寄与することが推定された.
この系のガラスに高電圧を印加したとき, 高抵抗から低抵抗に変化するスイッチングが観察された. この時, しきい値電圧V_thと極間抵抗Rの両対数は, 傾き2の直線関係にあり, またしきい値電界E_th(V_th/L) と極間距離Lの両対数は, 傾き-0.85の直線関係となった.
また一定高電圧を印加して, スイッチングまでの電流の経時変化からジュール熱を求めると, 印加電圧が高いとき加えられたジュール熱はかえって少なくなることが分った. これらの事実よりスイッチングはジュール熱による温度上昇のみでなく, 高電圧印加による伝導電子の増加を要因として説明された.

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To elucidate the redox equilibrium of high concentration transition metal ions in a highly viscous oxide melts with gas phase, the effect of iron concentration on the redox equilibriums in the oxide melts of FeO-Fe₂O₃-RP₂O₆ system (R=Mg, Ca, Ba) at 1200°C with CO₂ atmosphere, which oxygen partial pressure is about 10^-3.6 atm, was studied in this report.
The [Fe²⁺]/[Fe³⁺] ratios decreased at low iron oxide concentration and then increased after reaching their minimum values, as iron oxide concentration increased. These ratios also decreased at low iron oxide level and increased at high iron oxide level, as R was exchanged by Mg, Ca, Ba. The minimum values of [Fe²⁺]/[Fe³⁺] ratios shifted to the low iron oxide concentration by these exchange.
It is discussed from these experimental results that the reaction between free ferrous ion and ferric oxiacid ion such as
Fe²⁺+1/4 O₂+(x-1/2)O^2-=FeO_x^(2x-3)-
contributes mainly to the redox equilibrium at the low iron oxide concentration, and that the reaction between oxiacid ions of ferrous and ferric ions such as
FeO_y^(2y-2)-+1/4 O₂=FeO_x^(2x-3)-+{1/2-(x-y)}O^2-
contributes mainly at the high iron oxide concentration.
The relation between [Fe²⁺]/[Fe³⁺] and [O^2-], oxygen ion concentration, given by the combination of the above two redox reactions, agrees with the experimental results about the relation between iron oxide concentration and [Fe²⁺]/[Fe³⁺] ratios in various melts, if the oxygen ion concentration increases with the increase of iron oxide concentration.
The increase of oxygen ion concentration was recognized from the infra-red spectrums of glasses, obtained by quenching the melts in the redox equilibrium. Comparing the I. R. spectrums of FeO-Fe₂O₃-RP₂O₆ glasses with RP₂O₆ glasses, it was observed that the increase of iron oxide concentration corresponded to the exchanging R by Mg, Ca, Ba in RP₂O₆ glasses, the increase of basicity in the melts. This increase seemed to accompany with the change of the form (for example, chain length) of the phosphorus oxiacid ions in the melts. The formation of ferrous oxiacid ion in the melt was found to be possible from the shift of absorption peak by ferrous ion in the optical absorption spectrum in the above glass.
Discussion about activities of various ions was not successful in this paper.

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結晶化に伴うメモリースイッチングに着目して, CuO-V₂O₅-TeO₂系ガラスを熱処理して結晶化し, ガラス及び結晶化ガラスの導電率を検討した.
2元系ではCuOあるいはV₂O₅55mol%以上のガラスは見いだされなかったが, 3元系では遷移金属酸化物を最も多量に含有するガラスとして, 60CuO, 20V₂O₅, 20TeO₂なる組成のものが得られた. ガラスの導電率は, TeO₂を一定としてV₂O₅をCuOで置換するとき減少し, V₂O₅を一定としてTeO₂をCuOで置換するとき, 増加した. 25CuO, 45V₂O₅, 30TeO₂なる組成のガラスを熱処理するとき, V₂O₅, 未知相A及びCuTeO₃を析出し, 150℃における導電率は10^-3から10^-0.5Ω^-1・cm^-1に増加した. 導電率を高くする析出晶はV₂O₅及びA相であった. 55CuO, 15V₂O₅, 30TeO₂なる組成のガラスを結晶化するとき, 導電率はもとのガラスとほとんど変わらなかった. このときもう一つの未知相Bと, 少量のV₂O₅及びCuOを析出した. EPMA分析より, A相及びB相の組成はそれぞれ50V₂O₅, 25CuO, 25TeO₂及び20-25V₂O₅, 40-45CuO, 35-40TeO₂であることが見いだされた.

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ニオブ-チタン合金板(Nb:20,40,60,80wt%),チタン-バナジウム合金板(Ti:40,60,80wt%)およびバナジウム-ニオブ合金板(V:50wt%)を窒素中(1atm),1100～1350℃で窒化反応を行ない,反応の進行にともなう重量変化を熱テンビンで追跡して窒化反応速度を調べた。その結果,いずれの合金でも放物線則こしたがう速度定数が得られた。合金の窒化反応速度定数を比較すると,一定温度ではニオブ-チタン合金のうち20Nb,40Nb,60Nbはほぼ等しく,80Nbはそれより小さかった。チタン-バナジウム合金ではTi:40>60>80wt%の順であった。さらに窒化反応で生成した窒化相の深さを測定して窒化物析出速度を調べたところ,窒化増量による速度定数とは異ならた傾向を示した。ニオブ-チタン合金のうち高ニオブ合金(Nb:60,80wt%)試料については内部窒化の速度式を適用して窒化物成長速度に関する考察を行なった。

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In this investitigation, an instrument for electrical conductivity measurement employing four electrode method with alternating current has been designed and built, where a lock-in amplifier and constant current supplier of small alternating current have been incorporated for more precise and accurate measurement using lowpassing current. This instrument has then been shown to be successfully applied for electrical conductivity measurement of relatively high-conductive, molten slag, where the passing current of this instrument through molten slag is less than ImA when its specific conductivity is of order of several ohm.cm^-1.
Using this instrument, electrical conductivity of molten FeO-Fe₂O₃-SiO₂ slag have been measured at constant SiO content (SiO₂=28wt.%) at 1200°C under oxygen partial pressure of 10^-9-10^-12 atomosphere. Results show that the conductivity increase along with increase in oxygen partial pressure, i.e. increase in ferric ion content in slag. Conduction mechanism has also been discussed briefly.

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The redox equilibria of transition metals (V, Fe, Cr, and Ce) in phosphate melts (Li₂O-P₂O₅, Na₂O-P₂O₅, K₂O-P₂O₅, and NaPO₃-Ca(PO₃)₂) were investigated at 900 or 1000°C.
Using the oxygen ion activity obtained by an oxygen electrode method, the dependence of the redox equilibria of transition metals on oxygen ion activity was analysed. The same procedure of analysis was applied to the redox equilibrium in sodium silicate melt.
It was shown that with exception of chromium, the redox reactions are represented by the following:
RO_a^(m+n-2a)+=RO_a-h^(m+2h-2a)++(h-n/2)O^2-+n/4O₂
where R is transition metal, a and (a-h) are the numbers of the oxygen atoms constituting the oxyions of the oxidized and reduced metals, respectively, and (m+n) and m are the valences of the oxidizep and reduced metals, respectively. The (reduced)/(oxidized) ratio decreased with the increase of oxygen ion activity in both melts. The decrease was more rapid in acidic composition than in basic region.
That is, h decreased toward zero as the basicity increased. From the fact that the order of the redox ratio about element was different between phosphates and silicate melts, it was suggested that the coordination of solvent oxyanion also effects on the redox equilibrium of transition metals besides the oxygen ion activity.

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The electrical conductivities of CaO-SiO₂-Fe₂O₃ and Na₂O-SiO₂-Fe₂O₃ melts were measured in order to find out the behavior of Fe₂O₃ in these systems. Since Fe³⁺ ion is the amphoterci cation, it may be assumed that Fe³⁺ ion in octahedral sites will contribute to the electrical conductivities of these melts, but not Fe³⁺ ion in tetrahedral sites.
In the Na₂O-SiO₂ system, the oxygen coordination number of Fe³⁺ ion is changed at Na₂O/Fe₂O₃\fallingdotseq1. When the ratio of Na₂O/Fe₂O₃ in the melt is less than unity, Fe³⁺ ion tends to contribute to the electrical conductivity as a network modifier. On the other hand, Fe³⁺ ion will give no contributions to the electrical conductivity at the composition of Na₂O/Fe₂O₃>1. The ratio of Fe^3+(oct.)/Fe^3+(tetr.) also varied with the basicity of melts.

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標題の系のガラス化範囲を求めた. この系のガラスの導電率の組成及び温度依存性を100℃からガラス転移点 (T_g) の10°-20℃下の温度までの範囲で測定した. また密度, 熱膨張率, T_g, 遷移金属イオンの還元イオン分率を測定した. 電気伝導機構をMottによるスモール・ポーラロン・ホッピング理論によって検討した. これらのガラスには断熱近似 (トンネル係数αを零とする) が, 光学フォノン振動数 (ν₀) の値1けた以内程度の誤差で, ほぼ適用できた. しかし他の実験結果と矛盾しないようなα及びν₀の値は得られなかった. 導電率の組成依存性を決定する因子としては活性化エネルギーが支配的であった.
約10mol%以下のFe₂O₃を含有するガラスの導電率及び活性化エネルギーはV₂O₅-P₂O₅系ガラスと同様にV₂O₅濃度に主として依存する. これらのガラスのメスバウアー・スペクトル測定によればFe²⁺は検出されなかった. Feイオン対の電気伝導への寄与はVイオン対に比較して極めて小さいと考えられる.
約20mol%以上のFe₂O₃を含有するガラスの導電率はV₂O₅-P₂O₅系ガラスより高かった. Fe₂O₃の添加, あるいは20mol%以上のFe₂O₃によるV₂O₅またはP₂O₅の置換によって導電率は増加し, 活性化エネルギーは低下した. FeイオンはVイオンとともに電気伝導に寄与すると考えられる. これらのガラスについて測定された導電率は, Vイオン対及びFeイオン対がそれぞれ独立した伝導経路を構成すると仮定して, 断熱近似式によって計算された値よりはるかに大きかった. FeイオンとVイオンの間にホッピング伝導が起こる可能性が示された.

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