02_03859_SOW_.docx

STATEMENT OF WORK

TITLE: Inductive annealing for single crystal electrochemistry

I. BACKGROUND INFORMATION Electrochemical processes are central to the cost-effective manufacture of materials and the operation of devices that are used in a large array of technologies including advanced electronics and energy devices such as fuel cells. Rational strategies for the development and optimization of electrochemical interfaces require measurements that can locally monitor the reactivity on well-defined immersed electrode-electrolyte-interfaces to provide mechanistic insight to guide future designs and applications. The Materials Science and Engineering Division (MSED) is developing a suite of complementary measurement tools and methods that enable in situ characterization of electrodeposition, surface phase transitions and electrocatalysis that occur at single crystal metal-electrolyte interfaces. Electrochemical scanning tunneling microscopy (ECSTM) enables localized in situ measurement and mapping of the structure and dynamics of electrode surfaces. However, in order to perform meaningful experiments requires very flat and clean surfaces. This involves annealing of single crystal surfaces in an inert environment. Currently this entails using a high temperature H2-O2 torch to flame anneal Pt and Ir surfaces. For safety reason as well as improved process control we need to replace the flame annealing process with an induction heating process with active specimen temperature measurement and feedback control.

II. SCOPE OF WORK

a. OBJECTIVES/PURPOSE NIST requires a bench-top scale induction heater with a custom designed water cooled helical coil for annealing Pt, Ru, Au, Ni and Cu single crystals samples. The system shall also include a pyrometer and associated measurement and control electronics to provide real time temperature control during annealing.

b. GENERAL:

The Contractor shall provide a work bench model, water cooled 2.4 kW, 150-400 kHz RF induction power supply with a remote work head. A remote head is required to provide separation of the operator from the heated work piece to ensure safe operation. The work head design shall allow for a quick switch (2 minutes or less) between vertical and horizontal orientation of the water-cooled helical coil, by simple rotation of the work head as opposed to switching out coils. The heating coils shall be designed for heating: 1.) Cu single crystals that can be 2.5 cm in diameter and 0.4 cm in thickness and 2.) Au and Pt specimens that 1cm in diameter and 0.1 cm thick. The Cu crystal shall sit within a pyrex tube (provided by NIST) with an outside diameter of 3.5 cm that the RF coils will surround. The quartz tube shall contain a flowing protective inert gas atmosphere to protect the specimen surface during annealing. The single crystal specimens to be heated vary in size from Cu disk that are 2.5 cm in diameter and 0.4 cm thick, and shall be annealed at temperatures up to 900 C. In contrast, the Pt and Au disk 1 cm in diameter and 0.1 cm thick shall need to be annealed at temperatures up to 1400C for Pt and 900 C for Au and thus may require use a different RF coil in order to reach 1400 C with the limitation being that the inside diameter of the RF coil cannot be smaller than 2 cm.

The RF coils shall be engineered with fitting (e.g. Swagelok or equal) to enable easy attachment/detachment of the coils from the RF workhead piece. The salient characteristics of the Swagelok fitting are:

· Tube grip - The tube fitting hinging and colleting action provides more material of the back ferrule onto the tube adjacent to the tube grip. This extra material provides both direct axial support to the tube gripping function and colleting squeeze of the tube, unlike a bowing or bite-type ferrule. The tube fitting uses a patented hinging colleting action to achieve optimal tube grip instead of a bite-type design.

· Gas Seal. A gas seal is achieved by the burnishing or polishing that occurs between the front ferrule and the tube fitting body and the front ferrule and the tubing. This burnishing or polishing action accompanies concentrated zones of contact that seal the junction.

· Vibration Resistance. The hinging and colleting action directs more material of the back ferrule in close contact with the tube adjacent to the tube grip. The protected stress riser reduces the damaging effects of system vibration.

The power unit shall have electronic communication input ports for active temperature measurements via an external controller that takes electronic measurements from an optical pyrometer to enable active feedback control of the specimen during annealing.

The contractor shall provide a water to air heat exchanger for adequate cooling of the induction heating unit.

The high performance pyrometer shall be equipped with active double laser sighting to ensure accurate alignment and measurement of the specimens during annealing.

Minimal hardware specifications:

Power Supply Bench level induction heating unit, power supply not to exceed 35 lb, 24” in width, depth or height.

The power supply shall be water cooled, with an input power of 198-242 Vac, 50/60 Hz, 1 phase to yield output power of at least 2.4 kW between 150 kHz and 400 kHz. The line power (250 V, 15 A) cord should be at least 8 ft in length.

The contractor shall provide a water cooling unit compatible with the stated heating loads.

Separate Workhead

The workhead piece (heating coil) shall be separate (remote) from the power supply with at least 8 ft of the required RF cables and water lines being provided. The remote head shall also permit quick exchange between vertical and horizontal orientation of the working coils by simply rotation of the workhead. The workhead unit shall not exceed 15 lbs in weight and contain 0.33 microfarad FP or CSP150 (conduction cooled) 150 capacitors in parallel for a total capacitance of 0.66 microfarads. Tuning of the capacitance will be done in consultation with the customer.

RF coils

One RF coil shall be designed to surround a quartz tube, ~3.6 cm outside diameter, that will contain a flowing protective inert gas atmosphere of large Cu single crystals. (The quartz tube and gas will be provided by user). The Cu single crystal disk specimens vary in size with the largest being 2.5 cm in diameter and 0.4 cm thick.

A second RF coil is required to heat Pt single disk that are 1 cm in diameter and 0.1 cm thick up to 1400oC. The inside coil diameter shall not be less than 2 cm. All coils shall be engineered with Swagelok fitting to enable easy attachment/detachment of the coils from the RF workhead piece.

Controller The contractor shall provide a controller that, based on input from a pyrometer, shall enable separate closed loop single set point temperature control, RTD and thermocouple inputs, The control shall provide an upper limit of 50 to 200 msec scan rate and programming instruction along with 24 V DC power supply, controller housing and a 10 ft power cord.

Pyrometer and Electronics A high performance optical pyrometer with double laser spot marking to ensure correct specimen alignment and stable positioning for controlled heating and cooling, with a temperature range of 250 C to 1800 C, optical resolution 300:1 and a focus of 0.7 mm@200 mm, spectral range 2.3 microns, temperature resolution of 0.1 C, system accuracy of +/- 0.3% or +/- 2oC, Repeatability of 0.1 % or +/- 1oC, 8-36 VDC power supply, output/analogue 0/4-20 Ma, 0-5/10 V, Class II laser 635 nm, 1 mW, on /off via electronics or software. Sensor shall come with mounting nut, mounting bracket, 3m cable, controller with LCD-display with programming keys and manual.

The pyrometer output shall be compatible and fully integrated with the controller.

System Integration and Assembly The RF induction heating unit, water cooling unit, controller, and pyrometer units shall be fully integrated such that assembly of the units and first operation can be accomplished by customer within 4 hours.

III. PERIOD OF PERFORMANCE

60 days after award.