軟磁性材料用於多種應用，例如感應器中之芯材、電機之定子及轉子、致動器、感測器及變壓器磁芯。傳統地，軟磁芯(例如電機中之轉子及定子)係由堆疊之鋼層板製得。軟磁性複合物亦可基於軟磁性顆粒，通常為基於鐵之軟磁性顆粒，在每個顆粒上具有電絕緣塗層。藉由壓實絕緣顆粒獲得軟磁性組件。較藉由使用傳統鋼層板所可能達成者，使用此等呈粉末形式之磁性顆粒使得可產生可攜載三維磁通量之軟磁性組件，從而容許更高設計自由度。 本發明係關於基於鐵之軟磁性複合粉末，其磁芯顆粒經精心選擇之塗層塗佈，使得材料性質適用於藉助壓實粉末及隨後熱處理製程製造感應器。 感應器或反應器係可儲存呈磁場形式之能量之被動電組件，該磁場係由通過該組件之電流產生。 磁導率不僅取決於攜載磁通量之材料而且取決於所施加之電場及其頻率。在技術系統中，其通常稱為最大相對磁導率，其係在變化電場之一個週期期間量測之最大相對磁導率。 感應器磁芯可在電力電子系統中用於過濾不希望之信號，例如各種諧波。為有效地起作用，此應用之感應器磁芯應具有低的最大相對磁導率，此暗指相對於所施加之電場，相對磁導率將具有更具線性之特性，亦即穩定的增量磁導率µΔ
(如根據ΔB=µΔ
*ΔH所定義)及高的飽和通量密度。此使得感應器能夠以更寬範圍之電流更有效地工作，亦可將此表述為感應器具有「良好DC-偏壓」。DC-偏壓可根據在指定之所施加電場下(例如在4000 A/m下)最大增量磁導率之百分比來表示。另外，低的最大相對磁導率及穩定增量磁導率與高的飽和通量密度之組合使得感應器能夠攜載更高電流，在大小為限制因素時此尤其有益，由此可使用更小感應器。 為改良軟磁性組件之性能，一個重要參數係減小其磁芯損失特性。當磁性材料暴露於變化之場時，因磁滯損失及渦流損失二者所致而發生能量損失。磁滯損失與交變磁場之頻率成正比，而渦流損失與頻率之平方成正比。因此，在高頻率下渦流損失影響最大，且減小渦流損失並仍維持低程度之磁滯損失尤其重要。
此暗指期望增加磁芯之電阻率。 在尋找改良電阻率之方法時，已使用並提議多種不同方法。一種方法係基於使粉末顆粒經受壓實之前，在該等顆粒上提供電絕緣塗層或膜。因此，存在眾多教示不同類型之電絕緣塗層之專利公開案。關於無機塗層之公開專利之實例係US6,309,748、US6,348,265及US6,562,458。有機材料之塗層自(例如) US5,595,609得知。包含無機及有機材料二者之塗層自(例如) US6,372,348及5,063,011以及DE3,439,397得知，且根據此公開案，顆粒係由磷酸鐵層及熱塑性材料包圍。EP1246209B1闡述基於金屬之鐵磁性粉末，其中基於金屬之粉末之表面塗佈有由聚矽氧樹脂及具有分層結構之黏土礦物(例如，膨潤土或滑石粉)之精細顆粒組成之塗層。 US6,756,118B2係關於軟磁性粉末金屬複合物，其包含至少兩種封裝粉末狀金屬顆粒之氧化物，該至少兩種氧化物形成至少一個共同相。 為獲得高性能軟磁性複合組件，亦必須可使電絕緣粉末在高壓下經受壓縮模製，此乃因通常期望獲得具有高密度之部件。高密度一般改良磁性質。為保持磁滯損失在低程度下並獲得高的飽和通量密度，需要特別高之密度。另外，電絕緣體必須耐受所需壓實壓力，且不在經壓實之部件自模具射出時受損。此進而意指射出力不得過高。 此外，為減小磁滯損失，需要對經壓實部件進行應力釋放熱處理。為獲得有效應力釋放，熱處理應較佳在高於300℃並低於絕緣塗層將受損之溫度的溫度下，在例如氮、氬或空氣之氣氛中或在真空中實施。 本發明需要主要意欲在較高頻率，亦即高於2 kHz且尤其在5 kHz與100 kHz間之頻率下使用之粉末磁芯，其中較高電阻率及較低磁芯損失至關重要。較佳地，飽和通量密度應足夠高以用於磁芯小型化。另外，應可在不必使用模壁潤滑及/或升高溫度來壓實金屬粉末之情形下製造磁芯。較佳應消除該等步驟。Soft magnetic materials are used in a variety of applications, such as core materials in inductors, stators and rotors of motors, actuators, sensors, and transformer cores. Traditionally, soft magnetic cores (such as rotors and stators in motors) are made of stacked steel laminates. The soft magnetic composite may also be based on soft magnetic particles, usually iron-based soft magnetic particles, with an electrically insulating coating on each particle. The soft magnetic component is obtained by compacting the insulating particles. Compared with what is possible by using traditional steel laminates, the use of these magnetic particles in powder form enables the production of soft magnetic components that can carry three-dimensional magnetic flux, thereby allowing a higher degree of design freedom. The present invention relates to iron-based soft magnetic composite powders, the magnetic core particles of which are coated with carefully selected coatings so that the material properties are suitable for the manufacture of inductors by means of compacted powders and subsequent heat treatment processes. An inductor or reactor is a passive electrical component that can store energy in the form of a magnetic field generated by the current passing through the component. The permeability depends not only on the material carrying the magnetic flux but also on the applied electric field and its frequency. In technical systems, it is usually called the maximum relative permeability, which is the maximum relative permeability measured during a period of changing electric field. Inductor cores can be used in power electronic systems to filter undesired signals, such as various harmonics. In order to function effectively, the inductor core of this application should have a low maximum relative permeability, which implies that the relative permeability will have a more linear characteristic relative to the applied electric field, that is, a stable increase. Quantitative permeability µ Δ (as defined by ΔB=µ Δ *ΔH) and high saturation flux density. This allows the inductor to work more efficiently with a wider range of currents. This can also be expressed as the inductor having a "good DC-bias." The DC-bias voltage can be expressed as a percentage of the maximum incremental permeability under a specified applied electric field (for example, under 4000 A/m). In addition, the low maximum relative permeability and the combination of stable incremental permeability and high saturation flux density enable the inductor to carry higher currents, which is particularly beneficial when the size is the limiting factor, so it can be used more Small sensor. In order to improve the performance of soft magnetic components, an important parameter is to reduce its core loss characteristics. When a magnetic material is exposed to a changing field, energy loss occurs due to both hysteresis loss and eddy current loss. The hysteresis loss is proportional to the frequency of the alternating magnetic field, and the eddy current loss is proportional to the square of the frequency. Therefore, the eddy current loss has the greatest impact at high frequencies, and it is especially important to reduce the eddy current loss and still maintain a low level of hysteresis loss . This implies that it is desirable to increase the resistivity of the magnetic core. When looking for ways to improve resistivity, many different methods have been used and proposed. One method is based on providing an electrically insulating coating or film on powder particles before they are subjected to compaction. Therefore, there are numerous patent publications teaching different types of electrical insulating coatings. Examples of published patents on inorganic coatings are US 6,309,748, US 6,348,265, and US 6,562,458. Coatings of organic materials are known from, for example, US5,595,609. Coatings containing both inorganic and organic materials are known from, for example, US 6,372,348 and 5,063,011 and DE 3,439,397, and according to this publication, the particles are surrounded by iron phosphate layers and thermoplastic materials. EP1246209B1 describes a metal-based ferromagnetic powder, in which the surface of the metal-based powder is coated with a coating composed of fine particles of silicone resin and clay minerals with a layered structure (for example, bentonite or talc). US 6,756,118B2 relates to a soft magnetic powder-metal composite, which contains at least two oxides that encapsulate powdered metal particles, and the at least two oxides form at least one common phase. In order to obtain high-performance soft-magnetic composite components, it is also necessary to subject the electrically insulating powder to compression molding under high pressure, because it is generally desired to obtain high-density components. High density generally improves magnetic properties. In order to keep the hysteresis loss low and obtain a high saturation flux density, a particularly high density is required. In addition, the electrical insulator must withstand the required compaction pressure and not be damaged when the compacted part is ejected from the mold. This in turn means that the injection force must not be too high. In addition, in order to reduce the hysteresis loss, it is necessary to perform stress relief heat treatment on the compacted part. In order to obtain effective stress relief, the heat treatment should preferably be performed at a temperature higher than 300°C and lower than the temperature at which the insulating coating will be damaged, in an atmosphere such as nitrogen, argon or air or in a vacuum. The present invention requires powder magnetic cores that are mainly intended to be used at higher frequencies, that is, higher than 2 kHz and especially at frequencies between 5 kHz and 100 kHz, where higher resistivity and lower core loss are important. Preferably, the saturation flux density should be high enough for miniaturization of the magnetic core. In addition, it should be possible to manufacture magnetic cores without having to use mold wall lubrication and/or elevated temperature to compact metal powders. Preferably, these steps should be eliminated.
本發明之目標係提供新穎基於鐵之複合粉末，其包含基於鐵之粉末之磁芯，其表面塗佈有新穎複合電絕緣塗層。新穎基於鐵之複合粉末尤其適用於製造電力電子設備用感應器磁芯。由此材料製成之磁芯具有高機械強度、高電阻率、低磁芯損失、高增量磁導率及飽和通量密度。 本發明之另一目標係提供製造此等感應器磁芯之方法。 在一個實施例中，基於鐵之粉末組合物包含或含有磁芯顆粒(其係霧化鐵顆粒)及經磷塗佈之鐵合金顆粒(例如鋁矽鐵粉顆粒)。霧化鐵顆粒及鋁矽鐵粉顆粒藉由第一磷層分開塗佈。利用矽酸鹽層進一步塗佈經磷塗佈之霧化鐵顆粒，由此提供具有矽酸鹽塗層之鐵顆粒。然後將經矽酸鹽塗佈之鐵顆粒及經磷塗佈之鐵合金顆粒與聚矽氧樹脂混合。視情況可添加潤滑劑。 特定而言，根據第一態樣，本發明係關於包含以下各項之混合物之基於鐵之粉末組合物：(a)經矽酸鹽層進一步塗佈之經磷塗佈之霧化鐵顆粒；(b)由7重量%至13重量%之矽、4重量%至7重量%之鋁、餘量鐵組成之經磷塗佈之鐵合金顆粒，例如鋁矽鐵粉；及(c)聚矽氧樹脂。在基於鐵之粉末組合物中，霧化鐵顆粒對鐵合金顆粒之比率可自90/10至50/50變化，較佳介於80/20至60/40之間。 在一個實施例中，基於鐵之粉末組合物包含(a)霧化鐵顆粒及(b)由矽、鋁及鐵之混合物構成之鐵合金顆粒或由其組成；且經塗佈之顆粒(a)及(b)進一步與(c)粉末狀聚矽氧樹脂混合。霧化鐵顆粒(a)經磷層塗佈並然後經矽酸鹽層塗佈；鐵合金顆粒(b)經磷層塗佈。(a)上之矽酸鹽層含有鹼性矽酸鹽與含有層狀矽酸鹽之黏土礦物之組合，其中經組合之矽-氧四面體層及其氫氧化物八面體層較佳呈電中性，例如高嶺石。 另外，根據第二態樣，本發明提供製造經壓實及熱處理之組件(例如，感應器磁芯)之方法，該方法包含以下步驟： a)提供經塗佈之本發明第一態樣之基於鐵之粉末組合物； b)在介於400 MPa與1200 MPa間之壓實壓力下，在模具中在單軸壓製運動中壓實經塗佈之鐵及鋁矽鐵粉粉末混合物，視情況將其與潤滑劑混合； c)自模具射出經壓實之組件； d)在高達800℃之溫度下熱處理經射出之組件。 在較佳實施例中，在步驟b)中，模具係在升高溫度下，較佳地其中在步驟b)中，模具溫度介於25℃與80℃之間。 此外，本發明提供電磁組件，例如藉由上文方法製造之感應器磁芯。 與許多使用並提議之方法(其中期望低的磁芯損失)相比，本發明之特別優點在於不必在粉末組合物中使用任何有機黏合劑，該粉末組合物之後在壓實步驟中經壓實。因此可在較高溫度下實施生壓坯之熱處理而無任何有機黏合劑分解之風險；較高熱處理溫度亦將改良通量密度並減少磁芯損失。在最終經熱處理之磁芯中不存在有機材料亦容許該磁芯在具有升高溫度之環境中使用，而無因有機黏合劑之軟化及分解所致之強度減小之風險，且由此達成改良之溫度穩定性。The object of the present invention is to provide a novel iron-based composite powder, which comprises an iron-based powder magnetic core, the surface of which is coated with a novel composite electrical insulating coating. The novel iron-based composite powder is especially suitable for manufacturing inductor cores for power electronic equipment. The magnetic core made of this material has high mechanical strength, high resistivity, low core loss, high incremental permeability and saturation flux density. Another object of the present invention is to provide a method for manufacturing such inductor cores. In one embodiment, the iron-based powder composition includes or contains magnetic core particles (which are atomized iron particles) and phosphorus-coated iron alloy particles (such as aluminum silicon iron powder particles). The atomized iron particles and the aluminum silicon iron powder particles are separately coated by the first phosphor layer. The silicate layer is further coated with atomized iron particles coated with phosphorus, thereby providing iron particles with a silicate coating. Then, the silicate-coated iron particles and the phosphorus-coated iron alloy particles are mixed with silicone resin. Lubricant can be added as appropriate. Specifically, according to the first aspect, the present invention relates to an iron-based powder composition comprising a mixture of: (a) phosphorus-coated atomized iron particles further coated with a silicate layer; (b) Phosphorus-coated ferroalloy particles composed of 7 wt% to 13 wt% silicon, 4 wt% to 7 wt% aluminum, and the balance iron, such as aluminum silicon iron powder; and (c) polysilicon oxide Resin. In the iron-based powder composition, the ratio of atomized iron particles to iron alloy particles can vary from 90/10 to 50/50, preferably between 80/20 and 60/40. In one embodiment, the iron-based powder composition comprises (a) atomized iron particles and (b) ferroalloy particles composed of a mixture of silicon, aluminum and iron; and the coated particles (a) And (b) is further mixed with (c) powdered silicone resin. The atomized iron particles (a) are coated with a phosphorus layer and then coated with a silicate layer; the iron alloy particles (b) are coated with a phosphorus layer. (a) The upper silicate layer contains a combination of alkaline silicate and clay minerals containing layered silicate, wherein the combined silicon-oxygen tetrahedral layer and its hydroxide octahedral layer are preferably electrically neutral Sex, such as kaolinite. In addition, according to the second aspect, the present invention provides a method of manufacturing a compacted and heat-treated component (for example, an inductor core), the method includes the following steps: a) Provide a coated first aspect of the present invention Iron-based powder composition; b) Under the compaction pressure between 400 MPa and 1200 MPa, compact the coated iron and aluminum silicon iron powder powder mixture in the mold in a uniaxial pressing motion, as the case may be Mix it with lubricant; c) Inject the compacted component from the mold; d) Heat the injected component at a temperature up to 800°C. In a preferred embodiment, in step b), the mold is at an elevated temperature, preferably wherein in step b), the mold temperature is between 25°C and 80°C. In addition, the present invention provides electromagnetic components, such as inductor cores manufactured by the above method. Compared with many methods used and proposed (where low core loss is expected), the particular advantage of the present invention is that it is not necessary to use any organic binder in the powder composition, which is then compacted in the compaction step . Therefore, the heat treatment of the green compact can be performed at a higher temperature without any risk of decomposition of the organic binder; a higher heat treatment temperature will also improve the flux density and reduce the core loss. The absence of organic materials in the final heat-treated magnetic core allows the magnetic core to be used in an environment with elevated temperature without the risk of strength reduction due to the softening and decomposition of the organic binder, and this is achieved Improved temperature stability.
在本說明書通篇中，術語「層」及「塗層」可互換使用。 本發明提供基於鐵之粉末組合物，其包含以下各項之混合物： (a)經矽酸鹽層進一步塗佈之經磷塗佈之霧化鐵顆粒； (b)經磷塗佈之鐵合金顆粒，該等鐵合金顆粒由7重量%至13重量%之矽、4重量%至7重量%之鋁、餘量鐵組成；及 (c)聚矽氧樹脂。 鐵顆粒可呈具有低含量污染物(例如碳或氧)之純鐵粉形式。鐵含量較佳高於99.0重量%，然而亦可利用與(例如)矽合金化之鐵粉。對於純鐵粉或對於與有意添加之合金元素合金化之基於鐵之粉末，粉末除鐵及可能存在之合金元素外可含有自不可避免之雜質(由製造方法所致)所得之微量元素。微量元素以小量存在使得其不(或僅最低限度地)影響材料之性質。微量元素之實例可係至多0.1%之碳、至多0.3%之氧、各自至多0.3%之硫及磷及至多0.3%之錳。 鐵顆粒可經水霧化或經氣體霧化。霧化鐵之方法在文獻中已知。 基於鐵之粉末中磁芯顆粒之平均粒徑係由預期用途，亦即組件所適用之頻率確定。Sympatec HELOS儀器(Sympatec, Germany)用於使用根據日期為22/09/2000之SIS Standard SS-ISO13320-1之雷射繞射量測粒徑。由於塗層極薄，故磁芯顆粒之平均粒徑約等於經塗佈粉末之平均大小且平均粒徑可介於20 µm至300 µm之間。適宜的基於鐵之粉末之平均粒徑之實例係(例如) 20-80 µm (所謂的200目粉末)、70-130 µm (100目粉末)或130-250 µm (40目粉末)。 在基於鐵之粉末組合物中霧化鐵顆粒對鐵合金顆粒之重量比可自90/10至50/50變化，較佳介於80/20至60/40之間。 在一個實施例中，霧化之鐵顆粒經含磷層塗佈，其後經鹼性矽酸鹽塗層塗佈，且然後與經磷塗佈之鐵合金顆粒混合。 施加至裸露的基於鐵之粉末之含磷塗層可根據闡述於US6,348,265中之方法施加。此意指鐵或基於鐵之粉末可與溶解於諸如丙酮等溶劑中之磷酸混合，隨後乾燥，以在粉末上獲得含磷及氧之薄塗層。添加溶液之量尤其取決於粉末之粒徑；然而該量應足以獲得厚度介於20 nm與300 nm間之塗層。 或者，可藉由將基於鐵之粉末與磷酸銨溶解於水中之溶液混合或使用含磷物質及其他溶劑之其他組合來添加含磷薄塗層。所得含磷塗層使基於鐵之粉末之磷含量增加0.01%至0.15%。 鐵合金顆粒(b)可基本上由7重量%至13重量%之矽、4重量%至7重量%之鋁、餘量鐵組成，剩餘係雜質。此一粉末在領域內稱為鋁矽鐵粉。通常，鋁矽鐵粉基本上含有基於重量84%-86%之Fe、9%-10%之Si及5%-6%之Al。 在一個實施例中，矽酸鹽層可包含黏土顆粒及水溶性鹼性矽酸鹽。矽酸鹽層一般包含鹼性矽酸鹽與含有層狀矽酸鹽之黏土礦物之組合。矽酸鹽塗層可藉由將粉末與黏土顆粒或含有所定義層狀矽酸鹽之黏土及水溶性鹼性矽酸鹽(通常稱為水玻璃)之混合物混合，隨後藉由在20℃-250℃間之溫度下、視情況在真空中之乾燥步驟施加至經磷塗佈之基於鐵之粉末。 通常，水玻璃之特徵在於其比率，亦即(若適用)用SiO2
之量除以Na2
O、K2
O或Li2
O之量作為莫耳比或重量比。水溶性鹼性矽酸鹽之莫耳比應係1.5-4，包括兩個端點。若莫耳比低於1.5，則溶液變得過於鹼性，若莫耳比高於4，則SiO2
將沈澱。 層狀矽酸鹽構成矽酸鹽之類型，其中矽四面體以具有式(Si2
O5 2-
)n
之層形式彼此連接。該等層與至少一個八面體氫氧化物層組合形成組合結構。八面體層可(例如)含有氫氧化鋁或氫氧化鎂或其組合。矽四面體層中之矽可由其他原子部分地替代。該等經組合之分層結構可為電中性或帶電的，此取決於存在之原子。 已注意到，為實現本發明之目標，層狀矽酸鹽之類型極其重要。因此，層狀矽酸鹽應係具有經組合矽四面體層及氫氧化物八面體層之不帶電或電中性層之類型。此等層狀矽酸鹽之實例係存在於黏土高嶺土中之高嶺石，存在於千枚岩中之葉蠟石(pyrofyllit)或含鎂礦物滑石粉。 在一個較佳實施例中，50 wt%或更多係層狀矽酸鹽高嶺石。 含有所定義層狀矽酸鹽之黏土之平均粒徑應在0.1 µm至3.0 µm、或較佳0.1 µm至2.5 µm、或更佳0.1 µm至2.0 µm、或甚至更佳0.1 µm至0.4 µm、或0.1 µm至0.3 µm之大小範圍內。最佳地，黏土粒徑係0.25 µm。黏土顆粒之粒徑係藉由分析離心分析來測定。 欲與經塗佈之基於鐵之粉末混合之含有界定層狀矽酸鹽的黏土之量可介於經塗佈之基於鐵之複合粉末、亦即基於全部基於鐵之粉末組合物之0.2-5重量%之間、較佳介於0.5-4重量%之間。 欲與經塗佈之基於鐵之粉末混合之以固體鹼性矽酸鹽計算的鹼性矽酸鹽之量應介於經塗佈之基於鐵之複合粉末的0.1-0.9重量%之間，較佳介於基於鐵之粉末、亦即基於全部基於鐵之粉末組合物之0.2-0.8重量%之間。已顯示可使用多種類型之水溶性鹼性矽酸鹽，因此可使用矽酸鈉、矽酸鉀及矽酸鋰。 隨後將經磷及鹼性矽酸鹽塗佈之霧化鐵顆粒及經磷塗佈之鋁矽鐵粉顆粒與粉末狀聚矽氧樹脂混合。聚矽氧樹脂可以總混合物之0.3-1.5重量%、較佳0.4-1.0重量%間之量添加。 聚矽氧樹脂可含有50%-100%之苯基取代基、較佳75%-100%間且最佳100%之苯基取代基。 聚矽氧樹脂係含有Si-O-Si連接之主鏈之聚合化合物，其中矽原子具有一或多個有機取代基。可將聚矽氧之結構單元相應地歸類： 單官能單元(M)含有三個有機取代基、最通常甲基。 雙官能單元(D)含有兩個取代基；該等可係純甲基或苯基及甲基之組合，然而，由於立體阻礙，其不可僅含苯基。 三官能單元(T)具有一個有機取代基且此可係100%苯基取代基。 四官能單元(Q)不含有機取代基；其係四維具支鏈單元。 單官能單元及雙官能單元形成矽流體及鏈，而三官能單元及四官能單元係用於形成聚矽氧樹脂之緻密具支鏈三維網絡之交聯劑。 DT樹脂係自D及T單元形成之矽樹脂。樹脂係藉由烷氧基矽烷之水解及隨後縮合反應以形成聚矽氧烷來製得(US2,383,827及US6,069,220)。在烷氧基矽烷之情形下，烷氧基之水解及縮合反應並不充分完成。此意指製造後部分羥基及烷氧基保留於樹脂中。該等樹脂之性質受以下因素影響：聚矽氧原子上有機取代基之類型、有機基團R對Si之比率、有機基團之總含量及莫耳質量。交聯之程度，亦即有機基團之比率影響撓性及硬度。比率約為1產生硬的玻璃狀樹脂，而比率約為1.7得到軟的撓性樹脂。 較佳樹脂在純甲基取代聚矽氧樹脂至純苯基取代樹脂之範圍內；官能基可係選自由以下組成之群之一或多者：-O、-OH、-CH3
O、-C2
H5
O。 在一個實施例中，聚矽氧樹脂含有50%-100%之苯基取代基、較佳60%-100%間、75%-100%間或90%-100%間且最佳100%之苯基取代基。 在另一實施例中，聚矽氧樹脂中羥基、甲氧基及乙氧基官能基之總含量高於2 wt%、較佳高於5 wt%且最佳高於7 wt%。 在本發明之另一實施例中，聚矽氧樹脂之熔點高於45℃、較佳高於55℃且最佳高於65℃。 如上文所述基於鐵之粉末組合物可進一步包含潤滑劑。適宜潤滑劑可係有機潤滑劑，例如蠟、寡聚物或聚合物、基於脂肪酸之衍生物或其組合。適宜潤滑劑之實例係EBS (亦即伸乙基雙硬脂醯胺)、自Höganäs AB, Sweden購得之Kenolube®、諸如硬脂酸鋅之金屬硬脂酸鹽或脂肪酸或其其他衍生物。潤滑劑可以總混合物之0.05-1.5重量%、較佳0.1-1.2重量%間之量添加。 在另一態樣中，本發明亦提供製造經壓實及熱處理組件之方法，其包含以下步驟： a)提供本發明之基於鐵之複合粉末組合物， b)在介於400 MPa與1200 MPa間之壓實壓力下，視情況在模具之升高溫度下在模具中在單軸壓製運動中壓實基於鐵之複合粉末組合物，視情況將其與潤滑劑混合， c)自模具射出經壓實之組件， d)在非還原氣氛中在高達800℃之溫度下熱處理經射出之組件。 本發明亦提供根據上述方法製造之組件。該組件可係感應器磁芯，其較佳具有高於10000 µΩm、較佳高於20000 µΩm且最佳高於30000 µΩm之電阻率ρ；高於80、較佳高於90且最佳高於100之初始相對增量磁導率；及在20 kHz之頻率下、0.05 T之感應下小於12 W/kg之磁芯損失。 藉由本發明之材料達成之此良好飽和通量密度使得可使感應器組件小型化且仍維持良好磁性質。 壓實及熱處理 在壓實之前，可將經塗佈之基於鐵之組合物與適宜有機潤滑劑(例如蠟、寡聚物或聚合物、基於脂肪酸之衍生物或其組合)混合。適宜潤滑劑之實例係EBS (亦即伸乙基雙硬脂醯胺)、自Höganäs AB, Sweden購得之Kenolube®、諸如硬脂酸鋅之金屬硬脂酸鹽或脂肪酸或其其他衍生物。潤滑劑可以總混合物之0.05-1.5重量%、較佳0.1-1.2重量%間之量添加。 壓實可在400-1200 MPa之壓實壓力下在環境溫度或升高溫度下實施。 壓實後，使經壓實之組件在高達800℃、較佳介於600℃-750℃間之溫度下經受熱處理。熱處理時適宜氣氛之實例係惰性氣氛(例如，氮或氬)或氧化氣氛(例如空氣)或其混合物。 本發明之粉末磁芯係藉由將經電絕緣塗層覆蓋並與聚矽氧樹脂粉末混合之基於鐵之磁性粉末加壓成型而獲得。磁芯可具有高於15 MPa、或較佳高於20 MPa、或最佳高於25 MPa之抗彎強度(TRS)。磁芯之特徵可在於在2-100 kHz、一般5-100 kHz之頻率範圍內總損失較低，在20 kHz之頻率及0.05 T之感應下總損失小於12 W/kg。另外，磁芯損失在0-1 kHz之頻率範圍內亦應較低，較佳在1 kHz之頻率及0.5 T之感應下小於45 W/kg。另外，電阻率ρ高於10000 µΩm、或較佳高於20000 µΩm、或最佳高於30000 µΩm，且初始增量磁導率高於80、或較佳高於90、或最佳高於100。實例
以下實例意欲闡釋具體實施例且不應理解為對本發明範疇之限制。實例 1
使用鐵含量高於99.5重量%之純的水霧化鐵粉作為磁芯顆粒；粉末之平均粒徑係約45 μm。利用含磷溶液處理鐵顆粒，藉此獲得經磷塗佈之鐵顆粒。藉由在1 000 ml丙酮中溶解30 ml 85重量%之磷酸製備塗佈溶液，且每1000克粉末使用40-60 ml丙酮溶液。將磷酸溶液與金屬粉末混合後，將混合物乾燥。將所得乾燥經磷塗佈之鐵粉進一步與表1之高嶺土(自KaMin LLC, 822 Huber Road, Macon, Ga. 31217, USA購得)及矽酸鈉(以乾重計0.4%)摻和，並然後在120℃下乾燥。 用含磷溶液如上處理磨碎的鋁矽鐵粉(通常85%Fe、9.5%Si及5.5%Al)。將經磷塗佈之鋁矽鐵粉顆粒及經磷及鹼性矽酸鹽塗佈之鐵顆粒以70/30之鐵顆粒/鋁矽鐵粉之比率混合。將粉末混合物進一步與表1之自Wacker Chemie, Germany獲得之甲基聚矽氧樹脂(SILRES MK)及0.5%潤滑劑混合並在800 MPa及60℃下將其壓實成內徑為45 mm、外徑為55 mm且高度為5 mm之環用於磁性量測；並在800 MPa及60℃下將其壓實成IE-棒(定義)用於TRS量測。其後使經壓實之組件在700℃下在氮/氧氣氛(2500 ppm O2
)中經受熱處理製程0.5小時。 藉由四點量測法量測所得試樣之比電阻。藉由三點彎曲測試量測壓實件之抗彎強度。對於最大磁導率μmax
及矯頑磁性量測值，對於初級電路，將環「纏繞」100圈且對於次級電路20圈，使得能夠借助磁帶回線測量儀(hysteresisgraph) Brockhaus MPG 200量測磁性質。對於磁芯損失，借助Walker Scientific Inc. AMH-401POD儀器對於初級電路將環「纏繞」100圈且對於次級電路纏繞30圈。 當量測增量磁導率時，將環纏繞第三圈從而供應DC-偏壓電流。 除非另有說明，否則相應地實施以下實例中之所有測試。 表1
為顯示在第二塗層中存在高嶺土及矽酸鈉及使用聚矽氧樹脂對經壓實及熱處理之組件性質之影響，根據表1製備試樣A-H，該表1亦顯示來自測試組件之結果。 如自表1可見，具有主要磷塗層及由高嶺土及矽酸鈉組成之第二塗層之經霧化之鐵、具有磷塗層之鋁矽鐵粉及添加聚矽氧樹脂粉末之組合在維持高電阻率的同時顯著改良組件強度且因此降低磁芯損失。添加聚矽氧樹脂亦改良增量磁導率(比較試樣H與試樣A及E)。實例 2
為闡釋矽樹脂結構之效應，測試不同聚矽氧樹脂。比較純甲基聚矽氧樹脂與苯基/甲基樹脂及純苯基樹脂。另外，改變官能基(羥基及乙氧基)之量，參見表2。將經磷層及含有1%高嶺土及0.4%矽酸鈉之鹼性矽酸鹽層塗佈之鐵粉與經磷塗佈之鋁矽鐵粉混合(70/30鐵/鋁矽鐵粉)並然後與表2之0.4%聚矽氧樹脂及L2與A-蠟之0.5%潤滑劑混合物混合；並在800 MPa及60℃下將其壓實成內徑為45 mm、外徑為55 mm且高度為5 mm之環用於磁性量測；並在800 MPa及60℃下將其壓實成IE-棒用於TRS量測。其後使經壓實之組件在700℃下在氮/氧氣氛(2500 ppm O2
)中經受熱處理製程0.5小時。表2亦顯示來自測試組件之結果。表 2
如自表2可見，具有高羥基含量之純苯基聚矽氧樹脂有益，此乃因此產生高增量磁導率及低磁芯損失。藉由比較來自表1之試樣G與試樣M，闡釋使用潤滑劑混合物(L2及A-蠟)溫壓實之效應。經壓實磁芯之密度、磁導率及磁芯損失皆改良。Throughout this manual, the terms "layer" and "coating" are used interchangeably. The present invention provides an iron-based powder composition comprising a mixture of: (a) Phosphorus-coated atomized iron particles further coated with a silicate layer; (b) Phosphorus-coated ferroalloy particles , The iron alloy particles are composed of 7 wt% to 13 wt% silicon, 4 wt% to 7 wt% aluminum, and the balance iron; and (c) polysilicone resin. The iron particles may be in the form of pure iron powder with a low content of contaminants, such as carbon or oxygen. The iron content is preferably higher than 99.0% by weight, but iron powder alloyed with, for example, silicon can also be used. For pure iron powder or for iron-based powders alloyed with intentionally added alloying elements, the powder may contain trace elements derived from unavoidable impurities (due to the manufacturing method) in addition to iron and possible alloying elements. Trace elements are present in small amounts so that they do not (or only minimally) affect the properties of the material. Examples of trace elements can be at most 0.1% carbon, at most 0.3% oxygen, at most 0.3% sulfur and phosphorus, and at most 0.3% manganese. The iron particles can be atomized by water or by gas. The method of atomizing iron is known in the literature. The average particle size of the magnetic core particles in the iron-based powder is determined by the intended use, that is, the frequency to which the component is applicable. The Sympatec HELOS instrument (Sympatec, Germany) was used to measure the particle size using the laser diffraction of the SIS Standard SS-ISO13320-1 dated 22/09/2000. Due to the extremely thin coating, the average particle size of the magnetic core particles is approximately equal to the average size of the coated powder and the average particle size can be between 20 µm and 300 µm. Examples of suitable average particle sizes of iron-based powders are, for example, 20-80 µm (so-called 200 mesh powder), 70-130 µm (100 mesh powder) or 130-250 µm (40 mesh powder). The weight ratio of atomized iron particles to iron alloy particles in the iron-based powder composition can vary from 90/10 to 50/50, preferably between 80/20 and 60/40. In one embodiment, the atomized iron particles are coated with a phosphorus-containing layer, thereafter coated with an alkaline silicate coating, and then mixed with the phosphorus-coated iron alloy particles. The phosphorous coating applied to the bare iron-based powder can be applied according to the method set forth in US 6,348,265. This means that iron or iron-based powder can be mixed with phosphoric acid dissolved in a solvent such as acetone and then dried to obtain a thin coating containing phosphorus and oxygen on the powder. The amount of solution added depends especially on the particle size of the powder; however, the amount should be sufficient to obtain a coating with a thickness between 20 nm and 300 nm. Alternatively, the phosphorus-containing thin coating can be added by mixing iron-based powder with a solution of ammonium phosphate dissolved in water or using other combinations of phosphorus-containing substances and other solvents. The resulting phosphorus-containing coating increases the phosphorus content of the iron-based powder by 0.01% to 0.15%. The ferroalloy particles (b) can be basically composed of 7 wt% to 13 wt% silicon, 4 wt% to 7 wt% aluminum, the balance iron, and the remainder are impurities. This powder is called aluminum silicon iron powder in the field. Generally, the Al-Si Fe powder basically contains 84%-86% Fe, 9%-10% Si, and 5%-6% Al based on the weight. In one embodiment, the silicate layer may include clay particles and water-soluble alkali silicate. The silicate layer generally includes a combination of alkaline silicate and clay minerals containing layered silicate. Silicate coating can be achieved by mixing powder with clay particles or a mixture of clay containing a defined layered silicate and water-soluble alkaline silicate (usually called water glass), and then by mixing it at 20°C- It is applied to the phosphorus-coated iron-based powder at a temperature of 250°C, optionally in a vacuum drying step. Generally, water glass is characterized by its ratio, that is, if applicable, the amount of SiO 2 divided by the amount of Na 2 O, K 2 O, or Li 2 O is used as the molar ratio or weight ratio. The molar ratio of the water-soluble alkaline silicate should be 1.5-4, including two endpoints. If the molar ratio is lower than 1.5, the solution becomes too alkaline, and if the molar ratio is higher than 4, SiO 2 will precipitate. Layered silicate constitutes a type of silicate in which silicon tetrahedrons are connected to each other in the form of layers having the formula (Si 2 O 5 2- ) n. The layers are combined with at least one octahedral hydroxide layer to form a combined structure. The octahedral layer may, for example, contain aluminum hydroxide or magnesium hydroxide or a combination thereof. The silicon in the silicon tetrahedral layer can be partially replaced by other atoms. The combined layered structures can be electrically neutral or charged, depending on the atoms present. It has been noted that in order to achieve the objective of the present invention, the type of layered silicate is extremely important. Therefore, the layered silicate should have a type of uncharged or neutralized layer with a combination of a silicon tetrahedral layer and a hydroxide octahedral layer. Examples of these layered silicates are kaolinite found in clay kaolin, pyrofyllit found in phyllite, or talc containing magnesium minerals. In a preferred embodiment, 50 wt% or more is a layered silicate kaolinite. The average particle size of the clay containing the defined layered silicate should be 0.1 µm to 3.0 µm, or preferably 0.1 µm to 2.5 µm, or more preferably 0.1 µm to 2.0 µm, or even more preferably 0.1 µm to 0.4 µm, Or within the size range of 0.1 µm to 0.3 µm. Optimally, the clay particle size is 0.25 µm. The particle size of the clay particles is determined by analytical centrifugal analysis. The amount of clay containing defined layered silicate to be mixed with the coated iron-based powder can be between 0.2-5 of the coated iron-based composite powder, that is, based on the total iron-based powder composition Between weight %, preferably between 0.5-4 weight %. The amount of alkali silicate calculated as solid alkali silicate to be mixed with the coated iron-based powder should be between 0.1-0.9% by weight of the coated iron-based composite powder, which is more It is preferably between 0.2-0.8% by weight based on the iron-based powder, that is, based on the total iron-based powder composition. It has been shown that various types of water-soluble alkaline silicates can be used, so sodium silicate, potassium silicate, and lithium silicate can be used. Subsequently, the atomized iron particles coated with phosphorus and alkaline silicate and the phosphorus-coated aluminum silicon iron powder particles are mixed with the powdered polysiloxane resin. The silicone resin can be added in an amount of 0.3-1.5% by weight, preferably 0.4-1.0% by weight of the total mixture. The silicone resin may contain 50%-100% phenyl substituents, preferably between 75%-100% and most preferably 100% phenyl substituents. Polysiloxane resin is a polymer compound with a main chain of Si-O-Si connected, in which the silicon atom has one or more organic substituents. The structural units of polysiloxane can be classified accordingly: The monofunctional unit (M) contains three organic substituents, most commonly methyl. The bifunctional unit (D) contains two substituents; these may be pure methyl groups or a combination of phenyl groups and methyl groups, however, due to steric hindrance, they cannot contain only phenyl groups. The trifunctional unit (T) has an organic substituent and this can be a 100% phenyl substituent. The tetrafunctional unit (Q) does not contain organic substituents; it is a four-dimensional branched unit. Monofunctional units and bifunctional units form silicon fluids and chains, while trifunctional units and tetrafunctional units are crosslinking agents used to form a dense, branched three-dimensional network of polysiloxane resins. DT resin is a silicone resin formed from D and T units. The resin is made by hydrolysis of alkoxysilane and subsequent condensation reaction to form polysiloxane (US2,383,827 and US6,069,220). In the case of alkoxysilane, the hydrolysis and condensation reaction of the alkoxy group is not fully completed. This means that part of the hydroxyl and alkoxy groups remain in the resin after manufacture. The properties of these resins are affected by the following factors: the type of organic substituents on the polysiloxane atoms, the ratio of organic groups R to Si, the total content of organic groups and the molar mass. The degree of crosslinking, that is, the ratio of organic groups, affects flexibility and hardness. A ratio of about 1 produces a hard glassy resin, while a ratio of about 1.7 produces a soft, flexible resin. The preferred resin is in the range of pure methyl substituted silicone resin to pure phenyl substituted resin; the functional group can be selected from one or more of the following groups: -O, -OH, -CH 3 O, -C 2 H 5 O. In one embodiment, the silicone resin contains 50%-100% of phenyl substituents, preferably between 60%-100%, between 75%-100%, or between 90%-100% and most preferably 100%. Phenyl substituents. In another embodiment, the total content of hydroxyl, methoxy and ethoxy functional groups in the silicone resin is higher than 2 wt%, preferably higher than 5 wt%, and most preferably higher than 7 wt%. In another embodiment of the present invention, the melting point of the silicone resin is higher than 45°C, preferably higher than 55°C, and most preferably higher than 65°C. The iron-based powder composition as described above may further include a lubricant. Suitable lubricants can be organic lubricants, such as waxes, oligomers or polymers, fatty acid-based derivatives, or combinations thereof. Examples of suitable lubricants are EBS (ie ethylene distearylamide), Kenolube® available from Höganäs AB, Sweden, metal stearates such as zinc stearate or fatty acids or other derivatives thereof. The lubricant can be added in an amount of 0.05-1.5% by weight, preferably 0.1-1.2% by weight of the total mixture. In another aspect, the present invention also provides a method for manufacturing compacted and heat-treated components, which includes the following steps: a) providing the iron-based composite powder composition of the present invention, b) between 400 MPa and 1200 MPa Under the compaction pressure between the molds, the iron-based composite powder composition is compacted in a uniaxial pressing motion in the mold at the elevated temperature of the mold as appropriate, and mixed with the lubricant, as appropriate, c) injection from the mold Compacted components, d) Heat treatment of the injected components in a non-reducing atmosphere at a temperature of up to 800°C. The present invention also provides components manufactured according to the above method. The component can be an inductor core, which preferably has a resistivity ρ higher than 10000 µΩm, preferably higher than 20000 µΩm, and most preferably higher than 30000 µΩm; higher than 80, preferably higher than 90 and most preferably higher than The initial relative incremental permeability of 100; and the core loss of less than 12 W/kg under the induction of 0.05 T at a frequency of 20 kHz. The good saturation flux density achieved by the material of the present invention allows the sensor assembly to be miniaturized and still maintain good magnetic properties. Compaction and heat treatment Prior to compaction, the coated iron-based composition can be mixed with a suitable organic lubricant (e.g., wax, oligomer or polymer, fatty acid-based derivative or a combination thereof). Examples of suitable lubricants are EBS (ie ethylene distearylamide), Kenolube® available from Höganäs AB, Sweden, metal stearates such as zinc stearate or fatty acids or other derivatives thereof. The lubricant can be added in an amount of 0.05-1.5% by weight, preferably 0.1-1.2% by weight of the total mixture. Compaction can be implemented at ambient temperature or elevated temperature under a compaction pressure of 400-1200 MPa. After compaction, the compacted component is subjected to heat treatment at a temperature as high as 800°C, preferably between 600°C and 750°C. Examples of suitable atmospheres for heat treatment are inert atmospheres (for example, nitrogen or argon) or oxidizing atmospheres (for example, air) or mixtures thereof. The powder magnetic core of the present invention is obtained by pressing and molding iron-based magnetic powder covered with an electrically insulating coating and mixed with silicone resin powder. The magnetic core may have a bending strength (TRS) higher than 15 MPa, or preferably higher than 20 MPa, or most preferably higher than 25 MPa. The characteristic of the magnetic core is that the total loss is lower in the frequency range of 2-100 kHz, generally 5-100 kHz, and the total loss is less than 12 W/kg under the frequency of 20 kHz and the induction of 0.05 T. In addition, the core loss should also be low in the frequency range of 0-1 kHz, preferably less than 45 W/kg under the frequency of 1 kHz and the induction of 0.5 T. In addition, the resistivity ρ is higher than 10000 µΩm, or preferably higher than 20000 µΩm, or most preferably higher than 30000 µΩm, and the initial incremental permeability is higher than 80, or preferably higher than 90, or most preferably higher than 100 . Examples The following examples are intended to illustrate specific examples and should not be construed as limiting the scope of the present invention. Example 1 uses pure water atomized iron powder with an iron content higher than 99.5% by weight as the magnetic core particles; the average particle size of the powder is about 45 μm. The iron particles are treated with a phosphorus-containing solution, thereby obtaining phosphorus-coated iron particles. The coating solution was prepared by dissolving 30 ml of 85 wt% phosphoric acid in 1 000 ml of acetone, and 40-60 ml of acetone solution was used per 1000 g of powder. After mixing the phosphoric acid solution with the metal powder, the mixture is dried. The obtained dry phosphorus-coated iron powder was further blended with kaolin (purchased from KaMin LLC, 822 Huber Road, Macon, Ga. 31217, USA) and sodium silicate (0.4% by dry weight) in Table 1. And then dried at 120°C. Treat the ground aluminum silicon iron powder (usually 85% Fe, 9.5% Si and 5.5% Al) with a phosphorous solution as above. Mix the phosphorus-coated aluminum silicon iron powder particles and the phosphorus and alkaline silicate coated iron particles at a ratio of 70/30 iron particles/aluminum silicon iron powder. The powder mixture was further mixed with the methyl polysiloxane resin (SILRES MK) obtained from Wacker Chemie, Germany and 0.5% lubricant in Table 1, and compacted to an inner diameter of 45 mm at 800 MPa and 60°C. A ring with an outer diameter of 55 mm and a height of 5 mm is used for magnetic measurement; and compacted into an IE-rod (defined) at 800 MPa and 60°C for TRS measurement. Thereafter, the compacted component was subjected to a heat treatment process at 700°C in a nitrogen/oxygen atmosphere (2500 ppm O 2) for 0.5 hours. Measure the specific resistance of the sample obtained by the four-point measurement method. The flexural strength of the compacted part is measured by the three-point bending test. For the maximum permeability μ max and the measured values of coercivity, for the primary circuit, the loop is "wound" 100 turns and for the secondary circuit 20 turns, so that the magnetic can be measured with the hysteresisgraph Brockhaus MPG 200 nature. For the core loss, with the aid of Walker Scientific Inc. AMH-401POD, the loop is "wound" 100 turns for the primary circuit and 30 turns for the secondary circuit. When measuring the incremental permeability, the loop is wound a third turn to supply a DC-bias current. Unless otherwise stated, all tests in the following examples are carried out accordingly. Table 1 In order to show the influence of the presence of kaolin and sodium silicate in the second coating and the use of silicone resin on the properties of the compacted and heat-treated components, the sample AH was prepared according to Table 1, which also shows the results from the tested components . As can be seen from Table 1, the combination of atomized iron with a primary phosphorus coating and a second coating composed of kaolin and sodium silicate, aluminum silicon iron powder with phosphorus coating, and polysiloxane resin powder While maintaining high resistivity, the strength of the component is significantly improved and therefore the core loss is reduced. The addition of silicone resin also improves the incremental permeability (compare sample H with samples A and E). Example 2 is to illustrate the effect of silicone resin structure, testing different silicone resins. Compare pure methyl polysiloxane resin with phenyl/methyl resin and pure phenyl resin. In addition, change the amount of functional groups (hydroxyl and ethoxy), see Table 2. Mix the iron powder coated with a phosphorus layer and an alkaline silicate layer containing 1% kaolin and 0.4% sodium silicate with a phosphorus-coated aluminum silicon iron powder (70/30 iron/aluminum silicon iron powder) and Then it was mixed with 0.4% silicone resin in Table 2 and 0.5% lubricant mixture of L2 and A-wax; and compacted to an inner diameter of 45 mm and an outer diameter of 55 mm at 800 MPa and 60°C. A ring with a height of 5 mm is used for magnetic measurement; and compacted into an IE-rod at 800 MPa and 60°C for TRS measurement. Thereafter, the compacted component was subjected to a heat treatment process at 700°C in a nitrogen/oxygen atmosphere (2500 ppm O 2) for 0.5 hours. Table 2 also shows the results from the test components. Table 2 As can be seen from Table 2, pure phenyl polysiloxane resin with high hydroxyl content is beneficial, which results in high incremental permeability and low core loss. By comparing sample G and sample M from Table 1, the effect of warm compaction using the lubricant mixture (L2 and A-wax) is explained. The density, permeability and core loss of the compacted magnetic core are improved.
