Ti + LiAlH4 in a Parkhamov-type Experiment

Hi jeff .

Sounds like a worthwhile experiment- I have had similar experiences with other fuels, including the partial melting of a fused alumina tube. ETA- and the Kanthal heater- both witness to a temperature excursion above 1450C.

You might find the attached document of interest, not new here, I wrote and uploaded it quite a few years ago, it's a loose translation of a report by Russian experimenters working with Ti powders.

TALES FROM THE LABORATORY OF EXPERIMENTAL PHYSICS.pdf

I have melted several alumina devices, all began failure (melting ceramic, fire fountains from inside, large glowing, amoeboid hot spots that wiggle around then collapse into a large hole, etc.) somewhere shortly above 1150 and 1250 C outside temperature.

The Kanthal, if embedded, will easily reach its melting point before the surface temperature gets to close to that temperature due to the insulation and fairly poor heat conduction qualities of alumina ceramics. In some cases the Kanthal wire could be hundreds of degrees hotter than the alumina.

The internal core temperature is much more representative of the Kanthal wire temperature, but will lag slightly behind any pulses of input power.

Best to keep the outside temperature (and therefore the Kanthal temperature) a little bit lower for best results. Especially if one is expecting an extra burst of heat, which will naturally exceed the normal operating temperature. This will leave some headroom for any excess heat without instant subsequent failure of the device.

I always wondered why rather use an SS tube than alumina as fuel tube ?

Is there a secret to using an SS ?

Quote from jeff

Given that Ti has a very high affinity for hydrogen, I thought it might be interesting to run a Parkhamov-type experiment with Ti rather than Ni. In this case I loaded 100 mg LiAlh4 and 1g 200 mesh Ti powder into a 0.188" OD stainless tube 2" in length. The ends were plugged with fused quartz wool. Then the SS tube was placed in a 0.25" OD alumina tube around which was wrapped 32 T of 0.032" Kanthal wire. The entire apparatus described above fits into a 38 mm OD fused quartz tube that has connections to DC power, vacuum, and H2. The quartz tube is capped on both ends by machined endpieces with radial O-ring seals. I have no trouble maintaining 1e-6 Torr or better vacuum under continuous pumping. The experimental protocol went as follows.

1. Evacuate cell at room temperature to 1e-6 Torr or better.

2. Introduce 20 Torr dry H2

3. Step the heater voltage from 0V to 35V in 5V increments. This yields heater power from 12W to 540W and cell temperatures from ~100C to 1100C.

4. Add/bleed H2 from external source as required to maintain a pressure of < 100 Torr (This is the limit of the Baratron). I wanted to ensure that the system operated at sub 1 atm pressure for safety reasons.

5. Record alumina tube surface temperature and Delta T from the airflow calorimeter vs. heater power. I used an IR thermometer to monitor the temperature of the alumina tube.

The first run showed no excess heat as compared to a Ni + LiAlH4 + H2 mixture. The results were also nearly identical to running with an empty (no Ni or LiAlH4) cell. No excess heat, and the calorimeter delta T closely matched values for an empty cell.

The second run produced something unexpected. At a 35V heater voltage the Kanthal suddenly burned out. This was surprising since a 35V heater voltage has previously yielded

surface temperatures of <1100 C maximum. I was not able to record the cell surface temperature at the time of burnout because of heavy sputtering on the interior of the quartz tube. Also, the calorimeter did not have time to reach a steady state.

Upon disassembling the cell it was obvious that the SS tube and its contents exceeded 1500C: see attached photo. So the question is whether the sudden increase in temperature was due to chemical or LENR causes. I'll repair the apparatus and repeat the protocol and see what happens.

Comments are welcome.

Jeff

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Well,

You said to have used only 100 mg LiAlh4 and 1g 200 mesh Ti powder so how high you estimate the internal pressure reached ?

Good job jeff

Quote from jeff

"I always wondered why rather use an SS tube than alumina as fuel tube ? Is there a secret to using an SS ?"

The reason is most likely the same as that which convinced Parkhomov to include an SS tube in his later experiments. Lithium, or lithium compounds react with alumina far more readily that they will with SS. I first ran a Parkhomov-type experiment with Ni + LiAlH4 in an alumina tube. The result was a near instantaneous erosion of the alumina resulting in the lithium mixture melting (burning) through the alumina.

jeff

Have you seen evidence of metals diffusing into the alumina also with the SS tube? This could affect the conductivity of the ceramic material, which will further increase with (high) temperature in a positive feedback loop. It could even happen that the Kanthal wire melts in the hottest region but electricity can still be passed through the tube. Local temperatures > 1500°C will be easily possible in this way.

Quote from jeff

I first ran a Parkhomov-type experiment with Ni + LiAlH4 in an alumina tube. The result was a near instantaneous erosion of the alumina resulting in the lithium mixture melting (burning) through the alumina.

Interesting observation. I have done the same thing many times with pure fused alumina tubes (manufactured as thermocouple shields originally) and have never seen that happen. Perhaps all tubes are not the same?

Quote from jeff

"The Kanthal, if embedded, will easily reach its melting point before the surface temperature gets to close to that temperature due to the insulation and fairly poor heat conduction qualities of alumina ceramics. In some cases the Kanthal wire could be hundreds of degrees hotter than the alumina."

As part of the calibration process I measured simultaneously the external temperature of the Kanthal wire wound over the alumna tube (via IR thermometer) and the temperature inside the alumina tube (via type K thermocouple). There was a difference of 23-32 degrees C between the two, where the IR thermometer recorded the higher temperature. Given that the uncertainty of knowing the effective emissivity Kanthal and alumina, this temperature delta is acceptable and can be figured into subsequent measurements. In other words, I did not observe hundreds of degrees difference between the Kanthal temperature and that inside the alumina tube.

Another point: the fact that the SS tube melted indicates that temperatures inside the alumina tube (and presumably inside the SS tube) exceeded the MP of stainless steel (~1400 C). An exothermic reaction inside the SS tube, combined with Joule heating, would account for the melting of the SS tube as well as that of the Kanthal wire.

Kanthal wound on the outside is not embedded, and will generally last longer at the upper temperature range.

However, the coiled winding radiates and conducts heat into the center of the tube from all sides. This creates a much higher temperature zone in the core than the outside which has radiation and convection to reduce the temperature. At steady state, the core temperature will begin to approximate the heating wire temperature. A small diameter tube might not have such steep temperatures gradients from outside to inside as larger ones. The emissivity of the Kanthal, oxidized, should be around 0.75, but probably will be difficult to differentiate from the SS tube if the windings have an air space between them (but that helps the Kanthal last longer). However, an external wound coil, with gaps between wire wraps, wastes most of the heat directly to the environment and only about a third or so of the Joule heat actually goes into the device.

Another thing to consider is small dents, nicks, and perhaps stretched sections of Kanthal that may be considerably weaker, and have a local resistance difference from the bulk of the wire. The Kanthal wire will fail at such locations much sooner than the rest of the wire. For example, the wire could be 1200 C everywhere except one point where it is 1300 C due to a 5mm long dented wire section, then a tiny extra bit of power pushes the already hot spot over the melting point.

It is a bit tricky, but the Kanthal coil wire itself can be used as an RTD while operating.

People have been claiming excess heat has been wrecking hot tube devices for years, but it is actually a very common, mundane, heat failure mode. Once the device is tested and sturdy enough to prevent most mundane failures, then ascribing excess heat to the melting may be more appropriate.

Quote from Paradigmnoia

Once the device is tested and sturdy enough to prevent most mundane failures, then ascribing excess heat to the melting may be more appropriate.

That was certainly the case in the incident I described- there were 3 other matched systems runninh on an identical heat regime at the time, no problems with those.

As you may recall, I did a long series of similar Glowstick ("GS") experiments. For GS4 I used a Nickel fuel capsule inserted in the Alumina reactor. The first image below shows the remains of the fuel capsule after reaching 1230°C in the core. The second image shows similar destruction of the SS316 fuel capsule from GS5.2, which reached 1180°C. That experiment produced COP ~1.1 for nearly 1 hour, and a clear Bremsstrahlung gamma signal far above background level.

Both these experiments used Ni powder with about 15% LAH by weight.

So if i have well understood the SS tube you added was used to protect the first alumina one.

From your side, what was the pressure reached with your LAH considering the dead volume ?

Quote from magicsound

As you may recall, I did a long series of similar Glowstick ("GS") experiments. For GS4 I used a Nickel fuel capsule inserted in the Alumina reactor. The first image below shows the remains of the fuel capsule after reaching 1230°C in the core. The second image shows similar destruction of the SS316 fuel capsule from GS5.2, which reached 1180°C. That experiment produced COP ~1.1 for nearly 1 hour, and a clear Bremsstrahlung gamma signal far above background level.

Both these experiments used Ni powder with about 15% LAH by weight.

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Quote from Cydonia

So if i have well understood the SS tube you added was used to protect the first alumina one.

From your side, what was the pressure reached with your LAH considering the dead volume ?

The GS reactor was designed as a differential thermometric system, with a long reactor tube divided into two measurement regions. One side had a capsule with inactive filler (Alumina powder) and the other with the active fuel under test. The drawing below shows the construction details of the reactor.

The fuel capsule system was used to make the assembly easier and to keep the reactants separated. The pressure from the LAH was substantial, and was bled off as the temperature increased, to keep within a target range as specified by Parkhomov. In an early test of the GS design (at the HUG lab) we had a dramatic RUD event, which I discussed here. There's even a video of the event that I'll dig up if there's interest.

Show us again please.

Quote from Alan Smith

Show us again please.

The 4+-hr long video of the entire test is at https://tinyurl.com/9d462wx8

The "BANG!" event is at 3:47:40. The clock in the video stream shows 00:17:33 UTC.

I hope these are as small as I tried to make them.

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Glass goo from hollow tube 920 C

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The Slab (Durapot IR test rat)

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The Slab cause of failure - Fire fountain Kanthal

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These were fun too. They could shoot liquid glass, and did not last long.

(1 ohm, 10 W resistors)

And these...

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About to die... pulsing, wiggling hot spot, brightening persistently..

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Really about to die now...

Quote from jeff

Alternatives to Joule heating.

Has anyone looked into the use of SiC in a microwave oven as a means of achieving high temperatures? SiC is a strong microwave absorber and should therefore work as a heating element; it can tolerate temperatures substantially higher than either Kanthal or alumina. Additionally, SiC is chemically inert to most compounds or elements at elevated temperatures. One problem I foresee is controlling precisely the microwave oven power. Perhaps some type of phase control circuit would work.

Jeff

Alexander Parkhomov began to use Silicon Carbide for his reactors at least some of his later publications of this type of reactor were made with SiC but we haven’t heard much of new experiments of this type from him for a while. He then began to do other kind of experiments with lightbulbs based on his slow neutrinos ideas.

Here is the SiC reactor paper,

The experiment lasted 7 months and Bob Greenyer presented the results in representation of Parkhomov at ICCF 22.

https://drive.google.com/file/d/10tPXOEGHfB95YQeOoePUftdByo7BVnvg/view