簡介
Combined Seebeck coefficient and resistance measurement system description
SeebSys塞貝克系統
塞貝克系統是一款在高溫和多種氣體環境下對小體積樣品自動測量塞貝克係數和電阻的系統。 整套系統包括樣品架,爐子,測量裝置,電源和內部加熱器,電腦和測量軟體。 所有裝置通過控制電腦軟體進行操控。
塞貝克系統不是一款簡單的“按按鈕-出結果”的裝置,而是一個模組化系統,允許最終用戶根據自己的特定需求調整設置。 而這也意味著更大的學習難度,對用戶的參與和技能提出了更高要求,但同樣也提供了極大的靈活性。
SeebSys塞貝克系統
塞貝克系統是一款在高溫和多種氣體環境下對小體積樣品自動測量塞貝克係數和電阻的系統。 整套系統包括樣品架,爐子,測量裝置,電源和內部加熱器,電腦和測量軟體。 所有裝置通過控制電腦軟體進行操控。
塞貝克系統不是一款簡單的“按按鈕-出結果”的裝置,而是一個模組化系統,允許最終用戶根據自己的特定需求調整設置。 而這也意味著更大的學習難度,對用戶的參與和技能提出了更高要求,但同樣也提供了極大的靈活性。
系統簡介
樣品(DUT)被安裝在ProboStat的樣品架上,與電極、熱電偶和電阻加熱器相連。 樣品架插在一個加熱爐中。 軟體會指示爐子是否達到目標溫度,並控制測量裝置和連接到內部加熱器的電源。
內部加熱器用於改變樣品上的梯度,萬用表用於測量熱電偶冷端的樣品電壓,熱電偶電壓,樣品電阻和熱敏電阻。 該軟體自動計算所有相關屬性,並採取預定義的操作來使過程自動化。
該系統還可以被延伸應用於盤狀樣品上的全自動范德堡( Van der Pauw) 測量法。
單個組件的規格
ProboStat™
ProboStat是一個與樣品區域有16個電線聯通的樣品架。 標準電極是鉑,熱電偶是S型。 ProboStat 的高溫區由高純度的氧化鋁材料製造。 內部空間可以由需要的氣體(惰性,氧化,還原,腐蝕性)填充或者通過,或者抽至低真空。
使用彈簧載入裝置將樣品以垂直位置懸掛在兩個電流電極之間。 將另外兩個用於四點電阻測量的電壓探針電極施加到樣品上。
ProboStat™在用於其他類型測量(需要附加部件)的替代方法方面提供了靈活性和可擴展性:電導率與T,pO2,pH2O等,阻抗譜,介電特性,損耗等,圓盤,范德堡( Van der Pauw),和條形,2、3和4電極,離子遷移數,
質子遷移數,IV特性,燃料電池元件和單電池測試,電極動力學,H/D同位素效應,電化學泵送,氣體滲透和氣體電催化出口, 感測器測試等方面的分析(例如GC或MS)。
有關內容,請參見 http://www.norecs.com/index.php?page=11&p=all。
爐子
專為ProboStat設計的立式分體爐,1700W,單相,最高溫度適用於標準版本1200°C。
儀器
數字萬用表和數位電源內置在一個外殼中,從背面連接。 儀器通過USB電線與計算機相連。
帶有樣品信號的BNC電線與ProboStat樣品架相連。
在電腦控制下具有信號切換功能的數字萬用表將自動連續測量所有所需的屬性:
該軟體將轉換並計算所有必要步驟,以顯示塞貝克係數和電阻率。 鉑電極中超過溫度梯度的熱電壓會自動從樣品電壓中減去。
電腦和軟體
一台裝有最新Windows操作系統和可以連接到設備所有必須線材的預配置筆記型電腦。 隨附軟體可控制實驗的各個部分:
可選:雷射印表機
薄膜樣品
對於非導電基材上的薄膜,可以進行相同的測量,但樣品和電極的製備將比正常樣品更為重要。詳情請諮詢我們(請詳細說明您的薄膜和基底材質)
作為初步資訊
mm級線材可能很難以可以正確測量的方式連接到小於µm厚的薄膜上(因為距離很重要)。為了獲得最佳效果,使用者通常需要在焊絲和薄膜之間添加中間電極,例如下圖所示:
這些中間電極需要由最終用戶通過例如濺射,氣相沉積,噴塗或噴塗來製備。
氣體
樣品池有兩個進氣口和兩個排氣口,例如允許根據氧氣分壓進行測量(不包括氣體供應系統)。
真空度:空氣進入樣品池的洩漏速率通常為0.01 mbar / min。
ProboStat的標準版本可用於氧化,惰性和還原性氣體以及濕(或乾)氣體。
對應不同氣體的不同選擇:
不鏽鋼版本也可用於許多腐蝕性氣體,例如氨,濕酸性廢氣等。
該系統可以配備一個封閉的高溫鋼管,電池可以在高壓(最高15 bar的空氣或惰性氣體)下運行,但這需要使用另一種類型的爐子。
其他注意事項
電極製備和測量精度
體積比電導率是根據原始數據計算得出的,結果的準確性取決於使用者提供的樣品橫截面和電壓電極距離的測量值。
對可能的樣品上電極的需求在很大程度上取決於用戶和樣品特定的挑戰。在許多情況下,只需彈簧載入並系紮提供給樣品的電極就足夠了,但在一些更具挑戰性的情況下,使用者需要通過絲網印刷、手繪、濺射、燒結一根細鉑絲或任何其他合適的方法來製備樣品上的電極。該手冊包含樣品製備示例,NORECS 很樂意為任何使用者特定的挑戰提供説明。
樣品體積
條狀樣品的最大橫截面限制為10mm。 樣品的最大長度約為50mm。 我們建議最小橫截面為5mm,長度為30mm。 當樣品表面形成氧化物時,電壓電極接點可以是點接觸,每面接觸或完全包裹在樣品周圍。
也可使用更小的樣品,但是要犧牲一定的測量精度:
有關更多詳細資訊,請參閱「電極準備和測量精度」一章。
儀器
數位萬用表
參數 | 值(24h) | 值(1年) |
電壓解析度 10nV | ||
電壓精度 | 10 ppm讀值 +/- 1.2 μV |
37 ppm 讀數 +/- 1.2 μV |
電阻解析度 1 μΩ | ||
電阻精度 | 9 ppm 讀值 +/- 0.14 mΩ |
72 ppm 讀值 +/- 0.14 mΩ |
如需更高精度,請洽詢我們。
電源
可程式設計 20V / 5A / 100W 電源。
SeebSys
The SeebSys is a system for automated measurements of Seebeck coefficient and electrical resistance on small samples at high temperatures and under various atmospheres. The full system consists of sample holder, furnace, measurement instrument, power supply and internal heater, computer and measurement software. All instruments are controlled by software running on the computer.
SeebSys is no 'simple push-button-get-results' instrument. It is a modular system allowing the end user to tweak any aspect of the setup to their specific own needs. This means steeper learning curve, elevated need for user involvement and skill but as said, offers great flexibility as well.
Brief system description
Specifications for individual components
ProboStat™
ProboStat is a sample holder with 16 electrical connections to the sample area. Standard electrodes are platinum and thermocouples are S-type. The hot zone area of ProboStat is built with high purity alumina parts. Inside volume can be filled and flushed with desired atmosphere (inert, oxidizing, reducing, corrosive) or pumped to low vacuum.
The sample is suspended between two current electrodes in vertical position using a spring load setup. Two additional voltage probe electrodes for 4-point resistance measurements are applied to the sample.
ProboStat™ offers flexibility and expandability in terms of alternative methods for other types of measurements (additional parts required): Conductivity vs T, pO2, pH2O, etc., impedance spectroscopy, Dielectric properties, loss, etc., Disk, van der Pauw, and bar geometries, 2, 3, and 4 electrodes, Ionic transport number, Proton transport number, I-V-characteristics, Fuel cell components and single cell testing, Electrode kinetics, H/D isotope effects, Electrochemical pumping, gas permeation and electrocatalysis with gas analysis (e.g. GC or MS) on outlets, Sensor testing, and so forth. See http://www.norecs.com/index.php?page=11&p=all for references.
Furnace
Vertical split furnace specially designed for ProboStat, 1700W, single phase, maximum temperature for the standard version 1200°C
Instruments
Digital multimeter and digital power source are built into one encasing with connections on the back side. The instruments communicate with the computer through USB cable. The BNC cables carrying sample signals connect to the ProboStat sample holder.
The digital multimeter with signal switching under computer control will continuously measure all required properties automatically:
The software will convert and calculate all necessary steps to display Seebeck coefficient and electrical resistivity. The thermo voltage in the platinum electrodes over temperature gradient is automatically subtracted from sample voltage.
Computer and software
A pre-configured laptop computer with latest Windows operating system and all required cables to connect to the devices. The included software allows control of all aspects of the experiment:
Optional: Laser printer.
Thin film samples
Same measurements may be possible for thin films on non-conductive substrates, but sample and electrode preparation will be more critical than on normal samples. Please consult NORECS AS for details (please explain your thin film and substrate in detail)
As preliminary info
Millimeter scale wires can be hard to connect to less than micrometer thick thin film in a way that can be properly measured (since the distances are important). For best results it is often required for the user to add intermediate electrode between the wire electrode and the thin film, for example as described in this picture:
Atmospheres
The sample holder cell has two ingoing gas connects and two outgoing gas connections allowing for example measurements as function of oxygen partial pressure (gas supply system not included).
Vacuum definition: The leakage rate of air into the cell is typically 0.01 mbar/min.
The standard version of ProboStat can be used with oxidizing, inert, and reducing atmospheres, as well as wet (or dry) gases.
Optional for atmospheres
The stainless steel version can be used also with many corrosive gases, such as ammonia, wet acidic exhaust gases, etc.
The system can be equipped with an enclosing high-temperature steel tube the cell can operate at high pressures (up to 15 bar of air or inert gas) but this requires use of another type of furnace.
。
Other considerations
Electrode preparation and measurement accuracy
The volume specific conductivity is calculated from raw data and the accuracy of the result depends on user provided measurements of sample cross section and voltage electrode distance.
The need for possible on-sample electrodes depend heavily on the user and sample specific challenges. In many cases it is enough just to spring load and tie the electrodes provided to the sample, but in some more challenging cases the user needs to prepare on-sample electrodes by screen printing, hand painting, sputtering, sintering a piece of thin Pt wire or by any other suitable method. The manual has examples on sample preparation and NORECS is happy to provide help on any user specific challenge.
Sample size
Bar shaped samples are limited to maximum of 10 mm cross section. The maximum length of the sample is about 50 mm. We recommend minimum of 5 mm cross section and 30mm length. The voltage electrode contacts can be point contact, per face contact or wrapped fully around the sample when oxides form on sample surface.
Smaller samples are possible, but on the expense of measurement accuracy:
Please refer to chapter‘electrode preparation and measurement accuracy’ for more details.
Instruments
Digital multimeter
Property
|
Value (24 hours) | Value (1 year) |
Voltage resolution 10 nV | ||
Voltage accuracy | 10 ppm of reading +/- 1.2 µ |
37 ppm of reading +/- 1.2 µV |
Resistance resolution 1 µâŠ |
||
Resistance accuracy | 9 ppm of reading +/- 0.14 mâŠ72 ppm of reading +/- 0.14 m⊠|
More accurate versions on request.
Power supply
Programmable 20V / 5A / 100W power supply